The M1911 Pistols Organization Forums Site - Amazing reduction in perceived recoil with a simple part change

John

20th March 2006, 12:24

Well folks, I am sure you all know by now, that our friend Johnny (1911Tuner), is a genius, right? And most of you must have heard of his preference, for a very specific style of firing pin stop.

It's an EGW firing pin stop, with a square lower edge. Johnny uses them, with a very minor break there, just make that edge a bit round and you are done. Actually, here is Johnny's instructions on how to modify the stock EGW firing pin stop:

Start with a smooth mill file and cut a light 45 degree bevel on the corner. Be careful to keep it straight across. Just lightly break the corner. Use a file that's at least as wide as the stop.

I use the file for the next step, but the stone will work. Slower, but slow is good on your first one.

Shape the radius by swiping the beveled corner on the stone with a rocking motion...like you're trying to polish a radius that's already there. The main thing is to keep it straight arcoss to prevent side-loading the hammer pin.

For what it's worth...Using it with just the bevel will work, and EGW even suggests a bevel only...likely because it's easier to instruct the first-timer in establishing a bevel than in cutting a radius. All you really need is to remove the sharp corner. I do the radius because...well...that's the way John Moses did it.

Well folks, last Saturday, I got the chance to shoot two 1911s, same guns, side by side. Both were setup with what Johnny considers the perfect setup. Recoil springs were 16 lbs, new ones. Mainsprings were 23 lbs, new ones too. The ammo was the same 230 gr Fiocchi FMJ. The only difference between the two pistols was that the first one had a standard, rounded firing pin stop, while the second had the EGW one.

Well folks, I can tell you this: The difference in the way the gun recoils is more than obvious. It's amazing. With Tuner's firing pin stop, the gun made a small jump, perfectly upwards (not to the side) and was back on target in no time at all. The other gun was jumping up and to the right, much more than the Tuner's fp stop equipped one.

Now, I've tested several recoil reduction devices, such as Hartts, Recoil Reducer, Sprinco's etc. None of them show me this much recoil reduction. None! With most of these devices, I had to try hard to see any perceivable difference in recoil. The difference with this setup is obvious, from the first 2 rounds fired.

I asked two other experienced shooters, to compare the two guns. The first one's comment was "Wow!". The second one was "These two 1911s do not use the same ammo". Both are extremely familiar with the 1911.

Overall, we spend more than 100 rounds comparing the two pistols and we all agreed that this is indeed (and by far) the best setup we have ever tried on the 1911.

I just thought I should share this with you.

This is an edit to this post, to register the part numbers for this firing pin stop, from Brownells, just in case someone wants them.

#296-000-058 is for Series 70s style guns.
#296-100-001 is for Series 80 guns.

RickB

20th March 2006, 14:48

EGW stops are in all of my 1911s. Since I don't get to see a big difference amongst my guns, I have to shoot other's guns to appreciate the benefit of the part. It should theoretically improve accuracy as well, as there should be a slight delay in unlocking.
I noticed a huge difference in the peceived recoil of my Detonics Combat Master, and a new version from Detonics USA. I had just completed a 150-round match with my gun, and am very familiar with its handling characteristics. I loaded up the new gun, and after touching off the first round, could not believe how much harder the gun recoiled.
When I put the EGW part in my Delta Elite, it completely eliminated the slight "tail" I was getting on my primer strikes. A lot of people think a heavier recoil spring will have an impact on unlocking speed/timing, but on my gun, I went from a 24# spring with the stock FP stop, to a 20# spring with the EGW FP stop, and the firing pin strikes are nice and round with the latter set-up.
It is a part that, unlike a FLGR and other parts that cause debate, has a real impact on how the gun shoots.

Hunter

20th March 2006, 14:53

I have also seen the firing pin stop at Johnny's house that you are talking about and it is a great idea to reduce recoil and also remove a little mechanical advantage from the slide and transfer it to the mainspring as added shock relief. That is the way Johnny explained it to me.

Hersh

20th March 2006, 17:04

John,

Could you post some pics of the proper bevel and radius ? I've read a bit about the EGW stop recently and would like to try one.

Thanks,

Hersh

nemesis

20th March 2006, 17:08

1911Tuner

20th March 2006, 17:38

No offense to Tuner but Dawson offers those in his catalog. I thought I had seen a good selection of them in the hard copy catalog but the online catalog only shows 2 cam profiles.

Dawson Precision Catalog: Page 12 (http://www.dawsonprecision.com/images/DPCatalog44.pdf)

None taken. The small radius isn't my idea and it isn't new. It was actually
the original radius in the old, pre 1911A1 pistols that was changed later at the
whining of the troops insistnece that the gun be made easier to hand-cycle with the hammer down...and it does make a difference.

My part in it has been to educate other folks who aren't aware of its effect on the gun...and that's why I can't seem to keep a couple on hand here. As soon as I let one of the guys shoot one of my guns, they ask how I get it to cycle so smoothly...and what type of recoil system that I use to hold the muzzle flip down. When I show'em what it is and explain it to'em, the response is pretty universal: "I WANT one!" Soooo...Mine all disappear and I gotta order more. In fact...I'm out of'em at the present time.

For the record...The recoil spring doesn't have anything to do with delaying unlock timing OR containing the higher pressure of the 10mm...and using a heavier one has very little effect on delaying the slide's rearward movement. Unlock timing is a mechanical event, and occurs at a predetermined point...regardless of the slide's speed. This predetermined point varies from gun to gun. Delaying the slide at the onset of movement delays the unlock of the barrel relative to the bullet's position IN the barrel...but the point that unlock begins remains the same. The only way to alter the unlock timing is to
change the center-to-center spacing between the holes in the link...or using a different length link...which can bring on big headaches if you don't have a full understanding of what happens.

Deacon Aegis

20th March 2006, 22:35

This is seriously good stuff, dang it Tuner, when are you going to get that book written?! I have dibs on five copies and I want 'em signed! :D Don't let that tard Kuhnhausen's ripping you off stop you from writing a real book of 1911 tuning wisdom! I want I want I want I want! Seriously bro, you're sitting on a goldmine!

John

20th March 2006, 23:57

OK folks, here are the pictures:

http://img.photobucket.com/albums/v323/sv1cec/Pict2059.jpg

This is an EGW square profile firing pin stop on the left, and a standard rounded profile stop on the right.

Here is how the bevel should be filed.

http://img.photobucket.com/albums/v323/sv1cec/Pict2096.jpg

http://img.photobucket.com/albums/v323/sv1cec/Pict2097.jpg

http://img.photobucket.com/albums/v323/sv1cec/Pict2098.jpg

And here is how it should not be filed. This is a stop that Johnny send me.

http://img.photobucket.com/albums/v323/sv1cec/Pict2060.jpg

As you can see, the bevel I created is not straight accross the width of the stop. This was the first one I worked on, and I managed to totally destroy it. So I keep it only for playing and experimenting.

Thank God, I always order more parts than I need, LORL.

sniper615

21st March 2006, 03:45

just wanted to ask how much metal you take off to make the cut. in the first picture the angled face is much larger than the in the second picture.

jeff1124

21st March 2006, 05:13

Why wouldn't EGW sell them with the bevel/radius already cut if the benefits are so dramatic??

1911Tuner

21st March 2006, 05:24

A couple of points...

The stops are available in Series 80 and pre-Series 80 types. The one shown here is a Series 80.

A true radius isn't absolutely necessary. In fact, George recommends a light bevel for those not adept at creating a clean radius with a file...and it works well.

The original specs called for a nominal .078 radius, but it varies from .075 to .080 inch. I've cut it as small as a 16th (.062) and as large as a 10th inch...depending on the application. i.e. The longer the slide, the smaller the radius. Remember that as the radius gets smaller, the more it resists the slide's rearward movement...and the more momentum it loses at the outset.
Commanders get .075 or so. 5-inch guns get a 16th. Officer's Model/Defender class get the 1/10th inch radius. Although that seems backward, remember that the slide's momentum plays a big role in taking it to full rearward travel. When the radius causes it to lose a lot of that at the beginning of the cycle, you can run into short-cycles if you go too small with it. I'm also a "Light Springer"...that is...I tend to go down on the recoil spring loading instead of up, and use standard 16-pounds in 5-inch guns...standard 16 pound springs trimmed to 24 coils or so in Commanders...and clip the inner springs on dual spring systems in the chopped guns in order to prevent mag timing issues on the RTB. So...adjust the radius accordingly. Start with a small one and test it with the recoil spring that you intend to use, along with a new mainspring. If you go with a lightened mainspring, you can get away with a smaller radius...and don't under-estimate the effect that this firing pin stop will have on the slide's rearward speed and momentum. I've seen guns that throw brass 10-12 feet change to dropping it 3-4 feet away with just the addition of a .062 radiused stop and a new standard mainspring...and I've seen guns that throw it the "ideal" distance of 6 feet, barely dribble it out of the port.

The additional benefit is that the stop is oversized and can be carefully sized to a light press-fit...which eliminates extractor clocking and having the stop fall out of engagement and tying up the gun if you let your firing pin spring go too long between changes. It's the best 15 bucks that you ever spent on your pistol.

1911Tuner

21st March 2006, 05:32

Why wouldn't EGW sell them with the bevel/radius already cut if the benefits are so dramatic??

LOL...After unrehearsed testimony, the skeptical still wonder.

The reason that they're sold without the radius is to allow the installer to tune them to a specific gun and application. See my last post for a better understanding. The original specs were designed for the original 5-inch guns
with standard spring...the only ones available at the time. Today, we have
many variants and springs in all sorts of ratings. The square bottom allows
for a much wider window of opportunity and fine-tuning of the gun.

John

21st March 2006, 05:46

Yeah, sure, that's a good explanation, but how about those of us who can't measure the radius and rely on eyeballing??? And what about those stupid enough who didn't know that they come in S70 and S80 versions? Good Lord, you are hiding information from us????

LoL, I guess I have to order some more of these beauties.

Sniper, remember, the second picture is a stop which is not properly fitted, it was filed more than needed, the picture is only used to show you the breaking area. (Gee, can't one make a mistake here?? The next two were perfect (for me, if Johnny could see them, I am sure he would think differently)).

Dr. Dickie

21st March 2006, 06:02

LoL, I guess I have to order some more of these beauties.

Sniper, remember, the second picture is a stop which is not properly fitted, it was filed more than needed, the picture is only used to show you the breaking area. (Gee, can't one make a mistake here?? The next two were perfect (for me, if Johnny could see them, I am sure he would think differently)).

I seems as if you could correct the bevel, couldn't you (or is there too much metal already gone?).
How did the gun preform with the stop cut that way John?

1911Tuner

21st March 2006, 06:10

John...Isn't the one that I cut for you a Series 70 type?

I've use radius gauges to check the stops, but found that I can get'em pretty close by eyeballing and comparing to a drill rod of the selected size, so I don't even bother with the gauges any more. It doesn't have to be exact,
but it should be even all the way across to avoid side-loading the hammer.

A final note if you decide to go with a simple bevel. Be sure to break the leftover corner on the back of the stop...the one that the hammer contacts
as the slide pushes it back. Doesn't have to be perfect...just smooth it up a bit to allow it to glide across the hammer. You can do a nice job on it by just
polishing it on a piece of 600-grit paper and using a "rocking" motion to slightly round the corner off. Back the paper up on a hard, flat surface...A piece of glass or flat steel stock will do. This operation won't take more than about 10-15 seconds. Do the same with the corner left at the bottom for a more finished appearance.

Dr. Dickie

21st March 2006, 06:22

.

A final note if you decide to go with a simple bevel. Be sure to break the leftover corner on the back of the stop...the one that the hammer contacts
as the slide pushes it back. Doesn't have to be perfect...just smooth it up a bit to allow it to glide across the hammer. You can do a nice job on it by just
polishing it on a piece of 600-grit paper and using a "rocking" motion to slightly round the corner off. Back the paper up on a hard, flat surface...A piece of glass or flat steel stock will do. This operation won't take more than about 10-15 seconds. Do the same with the corner left at the bottom for a more finished appearance.

Isn't the corner that impacts the hammer the same one that has the bevel?
Are you saying to smooth the corner at the top of the bevel?

P.S. I wish you guys would make a list so that I get everything in one order, the UPS guy has started getting his mail at my place :p
I just ordered some bushings from EGW

1911Tuner

21st March 2006, 06:33

Isn't the corner that impacts the hammer the same one that has the bevel?
Are you saying to smooth the corner at the top of the bevel?

P.S. I wish you guys would make a list so that I get everything in one order, the UPS guy has started getting his mail at my place :p
I just ordered some bushings from EGW

Doc...If you look at the hammer as the stop contacts it, you'll see that the top corner formed by the bevel is the first contact point. Just a little smoothing makes things work...well, smoother. Smooth is good!

When you order, make sure that you get the correct stop. The Series 80 type will work regardless, but not vice-versa. Also be aware that Commanders and other guns with the offset ejector may require a little relieving in the corner to allow it to clear the ejector. If your slide stops dead after installation...that's what is stopping it.

As a footnote...many of the custom smiths do know about the stop's influence...and have been installing the small-radiused stops on the custom 10mm buildups, with great success. They discovered that the 5-inch guns are afforded the same impact buffering with an 18-pound recoil spring, a small radius on the stop, and a 23-pound mainspring as with the large radius stop (7/32nds) a 20-pound mainspring, (the darling of the 3-pound trigger set) and a 22-pound recoil spring. I believe that it was Ned Christiansen
that experimented with it first...and it caught on. My enlightenment came
with seeing original stops in the old guns that I used to buy up, rebuild, and shoot to destruction in my younger, less foresighted day...and before EGW
started making their square-bottomed/tuneable stops...I searched the gunshow parts bins relentlessly for the old ones. Since the US Military had replaced the early stops with the "New Improved" versions many years ago...they were hard to come by...and I was forced at times to make my own. A very time-consuming exercise...and I'd like to give George a great big
THANKS, BUDDY!

Dr. Dickie

21st March 2006, 07:00

Doc...If you look at the hammer as the stop contacts it, you'll see that the top corner formed by the bevel is the first contact point. Just a little smoothing makes things work...well, smoother. Smooth is good!

Thanks Tuner.
Another UPS order in the making :p

John

21st March 2006, 11:04

John...Isn't the one that I cut for you a Series 70 type?

Yes Master, the one you send me was S70, but the five that Wichaka send me were S80, unfortunatelly.

A final note if you decide to go with a simple bevel. Be sure to break the leftover corner on the back of the stop...the one that the hammer contacts
as the slide pushes it back.

Hmm, I am not sure I understand which corner you are refering to this time. Can you please elaborate? I think that the hammer is first touched by that corner, which I filed a little. Which is the corner you refer to now?

And of course, I asked George for some more of these delights.

1911Tuner

21st March 2006, 14:13

John said:

>Hmm, I am not sure I understand which corner you are refering to this time.<
*******************

Hold the stop so that you're looking at it from the side. Look at the bevel.
Whenever a bevel is cut, it leaves two corners...one above and one below the bevel. The corner above the bevel is the one that the hammer will initially contact as the slide moves and the hammer starts to cock. Round that corner a little to let the hammer glide across it more smoothy. A couple of swipes on 600-grit paper should do it.

It's not a dire necessity...basically just a little finishing touch.

dr2e

21st March 2006, 16:23

1911Tuner

21st March 2006, 16:30

johnny, you could sell me prime farmland in the everglades!!! after reading all this fine info i went to the safe to look at the stops in my guns. would the semi-custom builders, nighthawk in this case, be installing the beveled stops? from what i can tell looking at them on the slide they look like the picture john posted. the bottom edge looks like it has a radius to it. this of course is the edge towards the back of the slide. am i all set and leave it alone or should i mess it up and tinker with it (i don't mean changing it will mess it up, i mean ME messing it up)?

They very well could be installing beveled stops or stops with the small radius.
Probably beveled, since it's more cost-effective and less time consuming that way. Seems that after a few of the custom smiths jumped on it with their Delta Elites, the others did a little research...or actually saw an old pistol with the original stop...and THEN did some research and/or testing...and decided that it was a worthwhile modification, which is actually a return to original design specs. That small, seemingly insignifigant change makes for a lot of difference in the function of the gun.

And...maybe they're starting to realize that ol' John Moses really DID know a lotta stuff about his pistol. ;)

mike h. buness

22nd March 2006, 11:48

1911Tuner

22nd March 2006, 14:26

Another fantastic mod from tuner!!! With the light target loads I normally run chould this cause a FTF or failure to hold open on an empty mag? Following the instructions I chould slowly increase the radius if the above did appear. Just answerd my own question..... Way to go Tuner! Mike.

If your light loads are run in a gun with standard spring rates...recoil and mainspring...Very possible, depending on how light the ammo is. I haven't had any trouble with 200-grain/800fps in 5-inch guns, but the brass
kinda dribbles out of the port and piles up beside my right foot.

dr2e

22nd March 2006, 14:47

here is fp stop out of nhc talon II. i guess you can call this "radiused" no?
sorry for bad quality. need to invest in photography lessons, read manual or tripod.
http://i33.photobucket.com/albums/d56/dr2e/Picture062.jpg

John

22nd March 2006, 15:07

Dr2E, what happened to that picture?

dr2e

22nd March 2006, 15:49

john, other than i stink with this camera i couldn't tell ya. like in my apology i either need to read the manual or take some lessons from my brother. he's the one who can take photos. for some reason the few that i took just wouldn't focus clearly. i posted the "best" of the lot.

John

22nd March 2006, 16:07

OK, I can see it now. No this is the standard way of beveling the firing pin stop. This is not the one Johnny recommends and the one I showed in this thread.

dr2e

22nd March 2006, 16:31

oh, now i see looking back at your picture. you show a standard like i am showing. an improved fp stop has less taken off. is that correct? oboy, i get to patronize another one of our vendors! mo' money, mo' money......... ;)

1911Tuner

22nd March 2006, 17:51

dr2e Quote:

>I guess you can call this "radiused" no?<
***********************

Yes. That's the now-standard 7/32nds radius.

mike h. buness

22nd March 2006, 20:24

After re-reading all the posts and Johnny's reply on this mod with light loads, I'll still get one to play with. The stock radius on my AO is in the 7/32 range and might benefit from a smaller corner. Checking the #58 Brownells catalog the EGW oversized firing pin stop discription does mention this as a mod for major power factor loads as well as a tighter fit on the extractor. I'll bet it's a backorder now, thanks to this thread!! O well got to try it anyway! Thanks, Mike.

sniper615

22nd March 2006, 23:14

so from what i've been able to understand from reading this thread and looking at the pics, the standard fp stop has too much metal missing for a 5" model? Is there any way someone could post a picture of the 3 different cuts for the different slides?

Jerry Keefer

24th March 2006, 10:23

With the light target loads I normally run chould this cause a FTF or failure to hold open on an empty mag?

Mike;
I've been putting these in target guns for some time now, with the addition of a 3 degree angle to allow the hammer rest further forward, which adds even more resistance; these are B/E guns with slide mounted optics, with no function related problems...and on 6 in slide 9mm PPC guns.. They work...

Jerry

Gammon

24th March 2006, 22:39

I find this thread quite interesting because I have experienced the opposite problem. I have been shooting a Para P-16 in IPSC competition with an EGW comp. The gun needs an 8 or 9lb spring to function with Major loads (155gr bullet at 1050fps); heavier springs would prevent the gun from cycling reliably. I wanted to use this pistol at a steel match where they warned competitors against using hot loads and required a 140 or lower power factor, with a threat of a match DQ for using hotter loads. I loaded up the proper power factor steel loads and immediately found that the pistol wouldn't function with an eight lb recoil spring (the lightest I had). I was using a stock main spring and didn't want to change, so the FP stop was the only part I could modify. You should see it. I reemoved so much metal that the stop impacts the hammer just below the firing pin. The metal was removed a little at a time until the pistol would function. Square FP stops will work wonders in some guns, but you must keep in mind that the stop has to be tuned to the gun and ammo. it is one small part in a complicated system.

1911Tuner

25th March 2006, 07:09

The light springs are necessary because the comp adds mass to the barrel...which in turn adds mass/weight to the slide for the first 1/10th inch of travel rearward...which is where the slide gains the necessary momentum to complete its recoil cycle. Basically, the compensator accomplishes the same thing as the small-radius stop....but via a different mechanism. When you combine that with the required power factor...the gun short-cycles.
Remember...Newton's Law governing equal and opposite action/reaction. The harder the bullet is driven forward, the harder the slide will be driven rearward...and vice-versa.

jaybo292

26th March 2006, 15:04

Would this same mod. work on a SA Micro Compact? It`s quite a handfull.
Thanks Jay

1911Tuner

26th March 2006, 17:07

Howdy jaybo.

Probably not. I've had two Micros recently with short-cycle induced failures to eject, even after installing lighter recoil springs. I finally resorted to increasing the FP stop radius over the OEM 7/32nds before the issue was resolved. Just not enough slide mass in the chopped pistols to keep the slide movin' to full travel in some of'em.

jaybo292

27th March 2006, 10:28

Thanks Tuner

Dr. Dickie

27th March 2006, 11:46

jaybo292,
I came that close to PM-ing you about your sig file, then I got it.
very subtle (or I am just slow!).

jaybo292

27th March 2006, 11:56

Dr.Dickie, I must be missing something.Sig file??

wichaka

28th March 2006, 00:48

1911Tuner

28th March 2006, 04:49

Tuner.......I got them EGW stops for John.......Brownells #296-100-001, they say they are for 70 & 80 1911's.

They show another EGW stop #296-000-058, any difference? This one doesnt say 70 or 80 series.

The ones with the -058 suffix are pre-Series 80 stops. The -100s will work in either. Both may need to be relieved for Commander/OM ejectors.

John

28th March 2006, 05:04

The difference I see between the ones Wichaka send me, and the one that Johnny send me is that the lower part (which acts as a continuation of the disconnector ridge) is narrower on the left side, on Steve's stops. Not to a degree that they won't work on a pre-Series 80, but narrower on the left side, never the less.

1911Tuner

28th March 2006, 05:44

Steve,

The -058 stop doesn't have the relief cut on the right side for the S-80 plunger lever. Either one will work in pre-80 guns, but the 80 type stop doesn't provide full width of contact with the hammer. Probably anal-retentive on my part...but I prefer full contact if possible. When the Series 80 pistols have the lawyer parts intact, you really don't have a choice, but if you have a choice, I think full contact is better.

John

28th March 2006, 06:03

Yeap, that's why I've ordered 4 more from George, this time I specified the pre-Series 80 ones.

brownie

3rd April 2006, 16:11

1911Tuner

3rd April 2006, 16:38

[QUOTE=1911Tuner]
...The original specs called for a nominal .078 radius, but it varies from .075 to .080 inch...

I have a dumb question about this: When you say a .078 radius, does that mean the length of the cut should be .078, or does it mean the cut should reflect the circumference of a circle of .078 radius?

Thanks

Howdy brownie,

Best way I can describe it and not get all tangled up is to line up the butt-end of a drill rod with the corner of the stop so that the tangent of the rod
sits flush with the rear and bottom edges of the stop. The portion of the arc
that's below the corner of the EGW stop is the radius that you want ON the corner. Note again that I use a smaller radius...about a 16th inch...on 5-inch guns, .075 or so on Commanders with 18-pound recoil springs...1/16th on Commanders with 16-pound springs...which REALLY makes'em sing...and 1/10th to 1/8th inch radius on Officer's Model/Defender-class guns...depending on how each gun functions. I either leave the 7/32nds radius alone on the 3-inch Micro...and have had to go to a full quarter-inch radius on some of'em to get'em to cycle. An important part of the effect is in using a standard 23 pound mainspring.

Substandard mainsprings that are installed in the effort to shave every ounce possible off the trigger action is...IMHO...counterproductive, and doesn't reduce the trigger pull enough to make it worth throwing the slide's cycle out of balance with the rest of the system.

If you really want to feel a difference, install a 25-pound mainspring with the 1/16th radius and a 16-pound recoil spring in a 5-inch gun. The brass will literally drop on your right foot. :p

brownie

3rd April 2006, 16:50

[QUOTE=1911Tuner]
Best way I can describe it and not get all tangled up is to line up the butt-end of a drill rod with the corner of the stop so that the tangent of the rod
sits flush with the rear and bottom edges of the stop...

Thanks. That explains it very clearly.

Dr. Dickie

4th April 2006, 06:07

Best way I can describe it and not get all tangled up is to line up the butt-end of a drill rod with the corner of the stop so that the tangent of the rod
sits flush with the rear and bottom edges of the stop.

I know that I am a bit dense when it comes to the magic you'all do so well, and your explanation was perfect Tuner; except on small thing. What is a "drill rod"? Is that of a specific diameter? or is the diameter of the radius (1/16th) the diameter of the rod? (so I could substitue a wooden rod).
I have to replace the FP stop in my Commander with an oversized stop as the standard size will simply drop out (and has dropped down when firing twice on me), so I am dying to try this.
Thanks

John

4th April 2006, 06:48

Get a firing pin stop from EGW and break the edge, like in the pictures (better, if you can), then use a 16 lbs 32-coil GM recoil spring and trim it to 23.5 to 24 coils. The added preload in the Commander usually produces a 16.5 to 17 pound spring. Good strong ejection with cases landing about 4-5 feet from the gun. Be sure to check for coil bind whenever using this technique.

That came from Johnny himself (as you say "God Given").

Dr. Dickie

4th April 2006, 09:00

1911Tuner

4th April 2006, 09:26

I know that I am a bit dense when it comes to the magic you'all do so well, and your explanation was perfect Tuner; except on small thing. What is a "drill rod"? Is that of a specific diameter? or is the diameter of the radius (1/16th) the diameter of the rod? (so I could substitue a wooden rod).
I have to replace the FP stop in my Commander with an oversized stop as the standard size will simply drop out (and has dropped down when firing twice on me), so I am dying to try this.
Thanks

The drill rod size is the diameter of the rod...the non-fluted part that goes into the drill chuck. Good luck finding a straight .0625 wooden dowel. :)

Go slow. Whether you go with a radius or bevel, it has to be straight across or the hammer will side-load and wallow out one pin hole in the frame.

A new, correct-length firing pin spring will probably cure the Dropped Stop Syndrome. The springs that are OEM in Series 80 slides are like the .40 S&W...Short and Weak. :D

Dr. Dickie

4th April 2006, 09:32

Thanks Tuner. I gotta give this a try (at heart I am a tinkerer).

brownie

4th April 2006, 10:26

The drill rod size is the diameter of the rod...:D

The terminology is a little confusing. Until reading your post I assumed that a 1/16 radius referred to the radius of the drill rod template rather than diameter. Good to have that cleared up.

Gammon

4th April 2006, 11:31

Wouldn't you be better off using a spring specifically designed for the Commander?

1911Tuner

4th April 2006, 11:41

Wouldn't you be better off using a spring specifically designed for the Commander?

Go look at the spring in a new Colt Commander and compare it to a new one in a Government Model. Except for the number of turns, they're the same... spacing between coils, and very likely the wire diameter too...with few exceptions.

I've kept data for years on OEM Colt springs. Have yet to find one in a Commander that tests at 18 pounds...and very few that went over 16.
Most OEM springs in 5-inch guns ran from 14.5 to 15.5 pounds at full, coil touching compression.

And finally...Ordering a Wolff Commander spring from Brownells costs you about 8 bucks. I can order a 10-pack of 32-turn, 16 pound springs for $35.00 and change. When ya wear out a spring a month, that can add up.

Clipping GM springs to length won't work in Officer's Models with the old,
tab-locked spring plug. Different spring altogether, although the OD of the outer spring is the same. The spacing between coils is wider.

wichaka

4th April 2006, 17:25

Been using the clipped full size springs in my Commanders for years.

Then there's the stock springs in 5" guns..............another reason why I use 14-16lb springs.........because that's what they come with from the factory..........even though they state 16lbs. I haven't had a Springfield yet test out at 16lbs.

InTheBlack

4th April 2006, 19:32

When fitting the stop, I suppose you want to take equal amounts off of the left & right side?

Except Tuner mentioned the Commander might have an offset extractor, so would you want to shift the center of the stop rightwards or leftwards?
***

Warning: the link to the Dawson site doesn't open a web page, it tries to open the entire 2006 catalog as a pdf file within your browser. That will either take forever, or take forever and instead crash your browser & maybe your computer.

I cannot find the EGW firing pin stop listed on the Dawson site. They have two stops at $8.00, the Series 70 is illustrated & looks "standard" and I presume the Series 80 is the same:

http://www3.mailordercentral.com/shootingstore/products.asp?dept=1166

Their website is pretty crappy... have to find an old paper catalog...

1911Tuner

4th April 2006, 19:45

The Commander has an offset ejector. The extractor is the same as any other. I may have typed extractor though...Senior moment/Brainfart city for me these days. :D

Equal amounts from both sides until the stop enters the slide with the extractor removed...then fit to the extractor by taking material off the right side and be sure that the firing pin will snap back in place freely after the final fit.

John

5th April 2006, 01:35

Warning: the link to the Dawson site doesn't open a web page, it tries to open the entire 2006 catalog as a pdf file within your browser. That will either take forever, or take forever and instead crash your browser & maybe your computer.

The banner in the Sponsors Panel links to the main web site and it does not load any pdf file. And why would a pdf file take for ever to load and crash your browser?

Check the link below, for EGW's oversized Firing Pin Stop.

http://egw-guns.com/catalog/index.php?cPath=34_41

Dr. Dickie

5th April 2006, 15:15

That was dead easy. I took a tiny bit off each side and it popped in with just the right fit (and boy were you ever right about firing pin spring Tuner- the one I got from Brownells in their pro spring kit was LOTS stronger than what was in my Commander).
Now, I have to ask. I just broke the sharp edge off the stop (then hit it with a stone to smooth the top edge), it looks to be even across the surface, but how critical do I have to be? Should I get a stereo microscope and check to see that it is dead even across, or is simple visual inspection good enough (I do not want to egg out my hammer pin hole!)?

1911Tuner

5th April 2006, 15:22

Dr. Dickie

6th April 2006, 06:06

Eyeballin' it is good enough Doc. If the shiny line made by the file is parallel across the top and bottom...it's good to go. A tiny bit of cattywampus
ain't that critical. The pin clearance in the hammer and frame holes will allow
for it.

Yours was a smiler. Wait'll ya run into one that has a tapered slot in the slide...or one that won't let the stop fall in until ya thin it about .003 inch or so. I've seen both in the same gun! :mad: Fortunately, those are pretty rare.

Thanks Tuner, I get to test it out tomrrow ;) .
I just wanted to say thanks again. I love to tinker and learn how things work (You just can't quit being a mechanic after you have been one). If I can visualize it, I can usually understand it, but when it comes to fooling around with a weapon I am not going to play around. Your descriptions of things has been a college level education in how a 1911 works (although I am still a freshman).
It really helps a lot to have an expert with the patience and understanding that you have here to help hold my hand (as well as John, Hawkmoon, wichika, and the rest of the gang).

InTheBlack

6th April 2006, 15:39

EGW also sells a Firing Pin Stop Gauge set for $30. How is it used? Is it worth having if you are going to fit up all your 1911s with the square stop?

gage:
http://egw-guns.com/catalog/product_info.php?products_id=63

stop:
http://egw-guns.com/catalog/product_info.php?products_id=36&osCsid=bd4fe3321e4d9568f37098b4d7e80b2a

1911Tuner

7th April 2006, 19:03

When you see the gauges, it'll come to ya as to how to use'em. Study it for a few minutes. There's no real need to gauge the FP stop radius anyway.
Sizing it exactly isn't that critical. As long as the radius is straight and even all the way across. As noted...many people elect to simply go with a small bevel on the stop. Either one will work, as long as it's straight.

InTheBlack

8th April 2006, 00:50

From the thumbnail picture I can't tell what they are going to gage. Rather not spend $30 to find out... I thought maybe they were thickness gages to match the stop to the slots. From what you say are they radius sizes?

1911Tuner

8th April 2006, 04:44

ITB,

That's not a radius gauge. That's basically a GO/NO GO gauge to let you predetermine how wide the firing pin stop recess in your slide is, so that you can file the oversized stop to fit without time consuming trial-and-error.
Well worth the bucks if you plan on fitting several stops.

garrettwc

12th April 2006, 11:48

1911Tuner

12th April 2006, 12:22

OK, resurrecting this old sticky inspired by the discussion in the other thread.

Tuner, if I am understanding correctly, if the bevel had been even across in John's second picture then that is what a proper one would have looked like, correct? You are only taking off the tiniest bit of metal?

Not the large recontour/rounded version in the first picture?

Correct on all counts. The large 7/32nds radius became standard at some point before the transition to the 1911A1 models...and most of the original military 1911s were retrofitted with the "New and Improved" stops..which is why an original .078 stop is rarely seen on pre-A1 USGI pistols.

garrettwc

12th April 2006, 15:15

Woo hoo! I learned something today. Guess I'll take the rest of the day off :p

InTheBlack

13th April 2006, 00:03

What's the right kind of file to do this with?

In general, are the files sold at Home Depot etc good quality, or should they be gotten from Midway or Brownells?

Gammon

13th April 2006, 01:21

Stay away from Home Depot! You need a much finer grade than is normally used in carpentry or home repairs. Brownells is a good source; I use a #2 cut Swiss pattern file for this kind of work.

John

13th April 2006, 01:26

I think I should take Wichaka's advice and order a set of files from Brownells. You think it was the file which didn't allow me to radius the EGW firing pin correctly? Buhh, pilot error on that one!

Hersh

13th April 2006, 18:04

I think I should take Wichaka's advice and order a set of files from Brownells.

John,

Here's the set a tech. at Brownells recommended for me. $22 bucks for 12 different shapes. It's all I'll ever need.

http://www.brownells.com/aspx/NS/store/productdetail.aspx?p=6700&s=16247

Pappy

13th April 2006, 18:15

Correct on all counts. The large 7/32nds radius became standard at some point before the transition to the 1911A1 models...and most of the original military 1911s were retrofitted with the "New and Improved" stops..which is why an original .078 stop is rarely seen on pre-A1 USGI pistols.

Johnny, why would they make the change in radius? Looks like to me it's to make it easier to rack the slide. Am I correct? Pappy

1911Tuner

13th April 2006, 19:07

Johnny, why would they make the change in radius? Looks like to me it's to make it easier to rack the slide. Am I correct? Pappy

Correct, Pappy.

The troops were required to carry the pistol hammer down on an empty chamber. They complained that the slide was too hard to hand-cycle in a hurry...and the Army Ordnance Department obliged.

1911Tuner

13th April 2006, 19:08

I think I should take Wichaka's advice and order a set of files from Brownells. You think it was the file which didn't allow me to radius the EGW firing pin correctly? Buhh, pilot error on that one!

I do mine with a 6-inch smooth mill file... :p

Gammon

13th April 2006, 21:40

John,

Here's the set a tech. at Brownells recommended for me. $22 bucks for 12 different shapes. It's all I'll ever need.

http://www.brownells.com/aspx/NS/store/productdetail.aspx?p=6700&s=16247

That's a great start, but you can never have too many files. Trust me, you will be buying more.

Gammon

13th April 2006, 21:48

PS I bought the same file kit and got some use out of it, but I find myself using a 6 inch Swiss pattern #2 cut file for a lot of my work (not in the kit) and files and stones designed for specific purposes: trigger channel stone, barrel lug file, exractor hook file, and various stones for trigger work.

InTheBlack

14th April 2006, 00:09

Needle files aren't at all right for this job. I want a file that is wider than the part so I can lay the file on the bench against a stop and draw the part towards me.

Midway sells Nicholson files. Its easier for me to order stuff from them.
Smooth cut mill file 10" part 243-705

John

14th April 2006, 00:11

I think Brownells just sold another kit!

wichaka

14th April 2006, 13:24

I start with a #2 swiss, then when the radius is almost there, finish it up with a #4 swiss.

Whatever you do..........don't skimp on the quality of your files!

Jammer Six

14th April 2006, 14:14

Dr. Dickie

15th April 2006, 04:57

On another issue, I have the trigger channel stone, but it doesn't fit into the trigger channel on my SA milspec. :confused:

I don't have a milspec, and I haven't tried my stone in my SA GI, but I have stoned two of my Colt's, and it did a great job of cleaning out and smoothing the channel (so the bow just dropped into place).
Does it not fit into the channel at ALL? (not the shoe channel, the bow channel--sorry if that is insulting, not meant to be ;) )

Gammon

15th April 2006, 09:58

On another issue, I have the trigger channel stone, but it doesn't fit into the trigger channel on my SA milspec. :confused:

This is puzzling. I have a dozen 1911s and clones and all have the same dimension channel for the bow, more or less; the stone fits in all of them. Perhaps Dr. Dickie is right.

Jammer Six

15th April 2006, 14:25

As it happens, I'm going to do some cleaning later on today, and I'll try one more time, and I'll get the item number off the tube.

But no, I haven't been able to get it into either the bow channel or the trigger channel.

I actually wondered if there was just something I didn't know, like they come oversized, and I'm supposed to grind them down, or something...

Gammon

15th April 2006, 23:58

Immortal_Ben

17th April 2006, 18:14

1911Tuner

17th April 2006, 18:21

this may seem like a stupid question, but as im fixing to order the parts to try this mod... when you shorten the recoil spring to 24 coils, which end of the weapon do you put the clipped end towards? or does it even matter? :D

Howdy Ben,

First off...The clipped spring goes in a Commander-length gun, (4.25 inches)
just in case we weren't clear on that. 5-inch guns use the standard-length spring. (32 coils) Standard Officer's Model guns won't work with a shortened, standard 32-coil spring.

If you have a Commander:

The spring will come with one open end and one closed. Clip from the open end. The closed end goes onto the guide rod.

Immortal_Ben

17th April 2006, 19:27

Thanks for the fast answer Tuner. I do indeed have two Commander sized Kimbers, being the Pro Eclipse II and the Pro Raptor II.

Cant wait for my parts to get going on this.

1911Tuner

17th April 2006, 19:31

Thanks for the fast answer Tuner. I do indeed have two Commander sized Kimbers, being the Pro Eclipse II and the Pro Raptor II.

Cant wait for my parts to get going on this.

Are those 4.25-inch guns...or 4-inch? If they're less than 4.25, the spring may have to be cut shorter, and may not work at all if the OEM spring's spacing between coils is different from the 5-inch guns and the Commanders. Might wanna check that to see if you need a proprietary spring.

Immortal_Ben

17th April 2006, 19:44

see now THIS is why you need to put out a book or something. they are 4in barrels, and i will be calling Kimber in the morning to see about the spacing and yadda yadda yadda.... you the man Tuner. thanks a ton

Dr. Dickie

18th April 2006, 06:08

If you have a Commander:

The spring will come with one open end and one closed. Clip from the open end. The closed end goes onto the guide rod.

Okay, I gotta ask (I know it is a problem, just ask my wife).
When cutting the spring, do you count the inital two coils as one (at the closed end where the first two coils are together)?
I know one coil will not make a huge difference, I am just very anal about doing things correctly.
Also, when I did this, I noticed that the cut government spring was about 3 coils longer than the standard commander spring. That's right, right?
Thanks

1911Tuner

18th April 2006, 11:44

Count every coil. The cut GM spring may have been three coils longer, or it may have just looked like it was because it hasn't taken a set.

Colt's OEM Commander springs tend to vary as to free length and number of coils. Average count is about 21.5-22.5 turns. When cutting the standard spring to length, always check for coil bind before firing the gun. 24 coils may work fine in one...and be a half-coil too long for another.

Dr. Dickie

18th April 2006, 13:06

M36

29th April 2006, 20:56

Maybe I have missed it but I am really confused on which EGW firing pin stop to order from Brownells. I have a SA mil-spec SS being shipped. Do I need the series 80 or 70 series? Also, are there any similar modifications that can be made to a SA Ultra Compact?

Are the 16# Wolf recoil spring and the 23# main spring that was posted early, the two that I need to get for this gun?

Thanks,
Jim

1911Tuner

29th April 2006, 21:07

Howdy M3, and welcome aboard.

I don't recommend using the small radius stop on a Micro. There's just not enough slide mass.

For the Springfields, order the Series 70 type stop...but either one will work.
For the full modification, you'll need to change the ILS mainspring housing internals as well...but you can use the stop with the ILS parts in place.
You'll need a standard mainspring and cap...and to make detail-stripping/reassembly, you'll need the little mainspring cap pin...the one that's missing from your housing near the upper right hand corner. Replacement of the firing pin and spring are recommended when the mainspring housing parts are changed. Springfield uses a proprietary firing pin in their .45 caliber pistols. Close to, but not quite the same as 9mm/.38 Super. Brownells lists it
in the Ed Brown section. Very good firing pins, and only about 5 bucks.

M36

29th April 2006, 21:14

1911Tuner

30th April 2006, 07:13

Tuner, thanks for getting back to me so quick. I dont know what ILS is. Should I get the 23# main spring?

Does ILS stand for internal locking system?

Ok, edit again. Sifting through the Brownells catalog was a lot easier than hunting throught their website. I have all the parts that you mentioned. I also found a main spring tool. Is that something I should get? And still the same for the 16# recoil spring?

Thanks again,
Jim

ILS means Integral Locking System. If your pistol came with a twin-pronged key, you have the system. If your mainspring housing only has the cap pin hole...with a pin in it...near the upper right corner...you have the standard set-up, and you don't need anything except possibly a fresh mainspring.

If yours does have the ILS system, there should be a mainspring tool included with the gun. It's a small pin, bent at about 30 degrees. If yours doesn't have the ILS, no tool is required to remove and replace the housing. To disassemble the non-ILS type housing, a vise, a small nail, and a pair of needle-nosed pliers are all that's required.

The 16-pound recoil spring is standard.

M36

30th April 2006, 09:11

Some of the research I have done on the ILS makes me think that a lot of SA owners remove it and return to the normal, non ILS system that the 1911's have. Is that fairly common since parts in the ILS tend to wear out faster?

John

30th April 2006, 09:17

I would say it has more to do with the fact that they do not want to have non-standard parts in their pistol, or a system which can render their pistol useless, when needed.

skipper

10th May 2006, 09:23

I have been watching this topic for some time. I finally have to post, though I HATE people who challenge the "pro" that specs the dimensions. I got around to getting some stops. As I went to fit the first I checked the radius of the stock "Cup" stop. According to my gages, the stock radius measures 7/32 (this does not appear to be a true radius). That would match a 7/16 dia. drill rod. When I cut a 1/32 RADIUS (that would match a 1/16 drill rod as recommended) it seemed to me that is almost a sharp edge that would cock the hammer at a speed exceeding that of the bullet. Are you all REALLY sure that is what you want to do? Seems as though that would be very hard on the lock work. After some research, I think I found the OEM spec that calls for a 1/16 radius (that would match a 1/8 drill rod). That's still speeding up the hammer cock speed about triple that of the stock radius.
Sorry to be a nit-picker, I intend no offense, I just don't want anyone to tear up a good gun because of a "typo".

1911Tuner

10th May 2006, 12:10

Howdy Skipper,

The original design specs called for a radius of .078 (nominal) and it ran from .070-080 inch. The 7/32nds radius came later, as a result of the Army Ordnance Department responding to the conscripts' complaints over the pistols being too hard to hand-cycle with the hammers down.

As for tearing anything up...I've been using the 1/16th radius in my beaters for years. (Had to make my own before George Smith of EGW quietly introduced his square-bottomed "tuneable" stops. Thanks George!) Two of the guns in question(1991A1 Colt GMs) are each on their third barrel, along with a complete frame/slide refitting...and have logged something over a quarter-million rounds collectively...on the OEM hammers, struts, and sears. Disconnects were replaced on the rebuild at somewhere around the 75,000 round mark. Poor things were worn to a nubbin, it seems. Nothing has broken, and nothing has failed...and except for the mainsprings, recoil springs, and firing pin springs...nothing other than the barrels, links, and one broken slidestop has been replaced.

Three other guns in the "Beater Battery" are approaching 50,000 rounds each with similar results. (A 1991A1 Colt GM...A NRM Colt GM...and a Norinco)

emiddio

10th May 2006, 12:44

im just curious -- whats wrong with using the square edge -- no radius -- and just letting a natural radius wear itself into the stop ?

wichaka

10th May 2006, 13:13

Back to the question of cutting down stock length Gov springs to fit 4" guns. Check you guns stock recoil spring to see if the spacing is the same, if so...........yes you can cut down the spring.

I have a Caspian 4" and have done it with it...............no abnormal wear. Again check for spring bind.

Seems a bit stange to me............you chop off 3/4" off a Gov slide to make a Commander, and they want you to use an 18lb spring, which is 2lbs more than the Gov.
Chop off another 1/4" and they want you to use a 22-24lb spring..........thats 4-6lbs heavier. Way too much my friends............

I run 14-16 in my Gov sized guns, 16-17 in Commanders..........and 18-20 in the 4" guns. Add the EGW firing pin stop, and you'll have a sweet shooting gun. Flat recoil.........very managable, no damage.

Herb Clark

10th May 2006, 13:39

I guess this is a most famous web site! I've been back ordered from Dawson for a month for their Firing Pin Stop!!!

wichaka

10th May 2006, 14:02

Herb call George at EGW today, and they'll get it shipped out by today. They are always in stock.

1911Tuner

10th May 2006, 14:07

im just curious -- whats wrong with using the square edge -- no radius -- and just letting a natural radius wear itself into the stop ?

For one thing, the radius...even a small one...lets the stop glide across the hammer a lot smoother than it would across a square corner. The other thing is that a sharp, square corner is an ideal place for a crack to start.

As for letting it wear its own radius, you'd be waiting for a long time for it to form, since the hammer and the stop are pretty close on the Rc Scale.

brownie

10th May 2006, 14:18

...the OEM spec that calls for a 1/16 radius (that would match a 1/8 drill rod)....

I think I'm getting confused. It seems that the way the term "radius" has been used in this thread, a 1/16 radius would be one that matches a 1/16 diameter drill rod. Now, you're saying that it would match a 1/8 drill rod. Someone please straighten me out before I do something stupid.

skipper

10th May 2006, 17:06

Brownie, you have asked the same question that I was referring to. A "radius" is one half the diameter of a circle. Therefore a 1/16 RADIUS would be one half of a 1/8 DIAMETER circle. If one were to cut a profile of a 1/16 DIAMETER circle you would wind up with a 1/32 diameter RADIUS, an almost sharp edge. That is the "typo" I fear has been made in this thread. If I'm wrong, I apologize profusely to those who posted the spec!!!!

Herb Clark

10th May 2006, 18:55

Herb call George at EGW today, and they'll get it shipped out by today. They are always in stock.

Thanks Wichaka, I'll have to get up the required $25 minimum order. Good excuse to by stuff!!!!!!!!!

skipper

11th May 2006, 10:50

Herb, call Brownells. They had the stops in stock. I got mine in two days and they don't have a minimum order.

Herb Clark

12th May 2006, 19:18

Thanks Skipper! Order placed!

53vortec

13th May 2006, 16:35

First off thanks for a great forum and all the knowledge that people have taken the time to post here!

I do have a question that I haven't seen addressed here, though:

Should I use the Series 70 or Series 80 slide stop in my S&W 1911PD (Commander Length)?

Thanks,
53vortec

1911Tuner

13th May 2006, 18:15

I do have a question that I haven't seen addressed here, though:

Should I use the Series 70 or Series 80 slide stop in my S&W 1911PD (Commander Length)?

Thanks,
53vortec

Series 80 type firing pin stop. All the slidestops are the same...

53vortec

13th May 2006, 18:27

Thanks! That would be the 296-100-001, correct?

Firing pin stop is what I meant, I just had a keyboard driver error. :D

Tom

19th May 2006, 17:13

Just recapping what I've been reading in this thread. The stop offered on Brownells, 296-100-001, which is for Series 70 and Series 80 pistols will work in both types, but the stop available, 296-000-058, will ONLY work in Series 70-type pistols (like the Springfield).

Is that correct?

1911Tuner

19th May 2006, 17:40

Correct. The -058 stop is for 70-type pistols only.

Tom

19th May 2006, 20:42

Might have to get one of those -058's for my new Operator! ;)

John

20th May 2006, 01:45

You are late, I cleaned them up from these stops. From now on, they will be sold only from M1911.ORG with the following stamp on them:

"M1911.ORG Gun Parts"
"Courtesy of 1911Tuner"
"The best recoil reduction"
"device you can get, at"
"a silly price."
"Sold Exclusively from"
"M1911.ORG"

Yeah, I know, to fit all that, the font will be pretty small, but you all have magnifying glasses, don't you?

Rookie

21st May 2006, 19:32

Ok, I have just become the proud owner of an RIA m1911a1. I was only going to make a single modification to it until i saw this thread! (I believe this is how always starts, what am i getting myself into). I plan to put some sights on it, and now I plan on replacing the firing pin stop. (and the list begins to grow).

After having read this whole thread twice, I have a couple of questions having never owned a 1911 before.
1) Would the RAI be a pre series 80 (ie Brownells #296-000-058). and if this isn't to far off topic, what are the differences in the series 70 and series 80 1911's

2) Having a 5" barrel i wanted to confirm that i would want to cut a .062 or 1/16 radius bevel in the new stop, correct so far.

3) Last but not least! Safety is always first! You could consider me an amateur when it comes to gunsmith work, say preschool level. So I want to confirm that this is a fairly safe modification for me to make. I am reasonably mechanically inclined and have a lot of patience, but no experience. Am I stepping off the deep end. Someone, anyone please warn me if this is the case. I will go pay someone to do it for me.

PS. This site and it’s forums are fantastic! Have already learned a lot.

John

22nd May 2006, 00:21

Yes, RIAs are pre-Series 80 and the difference between the series is explained in the Home Page, in the History section. And yes, this mod is as safe as it any mod can be, go ahead and do it.

mo' guns

22nd May 2006, 16:56

1911Tuner

22nd May 2006, 17:12

The EGW FPS is thicker than the original FPS. (at least the one in my RIA 5" GM) I noticed that the firing pin does not stick out of the EGW unit as much as the original FPS. Will the difference in thickness affect the FP strike? Does one need to take any stock off the face of the EGW FPS?

Sometimes. If you do, take it off the rearward face by drawing it along a mill file, and use a tapered stone or a countersink to deburr and chamfer the firing pin hole.

EDITED FOR BRAINFART:

Cut from the forward face if the stop is too thick to enter the slot.
To present more firing pin to the hammer, cut from the rear face...but be careful to keep it flat and square.

mo' guns

22nd May 2006, 17:47

I will try that tonight. Thank you for that quick response!

ambidextrous1

22nd May 2006, 21:03

While waiting for the arrival of my firing pin stops, I've done some planning and calculations.

I intend to form a 45 degree chamfer first, then form a radius by filing & stoning the excess material away.

I calculated the width of the chamfer, to be sure I don't remove too much material.

Let's call the radius R; then the width of the chamfer will be 0.4 R.

As an example, let's say you want a radius of 0.08 inches: Then the width of the chamfer will be 0.4 X .080 inches, or .032 inches. It's important to form the chamfer at 45 degrees for optimum accuracy.

In forming the radius, it's inevitable that the file (or stone) will be drawn across the 45 degree portion of the chamfer; it would be wise to make the chamfer a few thousandths narrower than your calculation.

I hope this will be helpful - good luck!

Hersh

22nd May 2006, 21:44

In forming the radius, it's inevitable that the file (or stone) will be drawn across the 45 degree portion of the chamfer; it would be wise to make the chamfer a few thousandths narrower than your calculation.

I hope this will be helpful - good luck!

Sounds helpful to me! I'm planning on experimenting with this and needed some hard numbers about the filing.

Hersh

Btw: John posted a pic earlier of how NOT to form the bevel, does anyone have a pic of a correctly modified stop?

John

23rd May 2006, 05:49

LoL, I could post one, if I could remember where I have installed Johnny's stop. He send me one some time ago, but now I am too confused to tell which one is which.

jaybo292

23rd May 2006, 12:18

Ahh, been in the medicine cabinet again. :lm:

ambidextrous1

23rd May 2006, 12:25

I hope to get my FP stops this week; I'll post a photo of a 'proper' chamfer,
if I can accomplish one.

Hersh

23rd May 2006, 16:58

I hope to get my FP stops this week; I'll post a photo of a 'proper' chamfer,
if I can accomplish one.

Out-freakin'-standing Sir!

Hersh

23rd May 2006, 16:59

LoL, I could post one, if I could remember where I have installed Johnny's stop. He send me one some time ago, but now I am too confused to tell which one is which.

John have you been into the Ouzo again?

Tom

23rd May 2006, 17:04

The stop is probably at the bottom of the bottle, like the Tequila worm! :D

John

24th May 2006, 02:07

So, this is what one gets, if he does not want to give you inaccurate information, and wants to be very precise? OK, you clever minds, here is how the stop should be filed.

http://img.photobucket.com/albums/v323/sv1cec/Pict2096.jpg

http://img.photobucket.com/albums/v323/sv1cec/Pict2097.jpg

http://img.photobucket.com/albums/v323/sv1cec/Pict2098.jpg

Now, I am going for my medicine again, as some of you suggested (Nescafe, shaken, ice cold).

Oh, I updated the first post in this thread as well, for the benefit of those who come in late.

jaybo292

24th May 2006, 03:52

John, Thanks for the pic. It helps alot. ;)

ambidextrous1

24th May 2006, 17:06

My FP stops have not yet arrived, and I continue to think about what I'll do when they get here (not a bad idea).

I believe the best approach is to file or stone a .030 inch, 45 degree chamfer on the stop and smooth it with a stone to remove any irregularities. This can be done before or after the stop has been fitted to the slide.

When all of this has been done, install the FP stop and go to the range. Shoot a lot of rounds if things are going well. Your work is complete.

If you are getting short cycles. the FP stop is robbing the slide of too much kinetic energy. Remove the stop and convert the upper half of the chamfer to an arc, ending smoothly with the rear of the stop. This will make it easier for the slide to move the hammer rearward, conserving its kinetic energy and (hopefully) eliminating the short-cycling problem.

If the weapon continues to short-cycle, set up the stop for a 45 degree cut, and take a few more thousandths off (how brave are you? .020 for the macho, .005 for the timid).

Repeat paragraphs 2 and 3 of this post.

If problems persist, take another cut at45 degrees (don't get impatient), and try again.

With this procedure, you should be able to produce one good firing pin stop, starting with one firing pin blank.

This post is subject to comments and corrections by 1911 tuner.

Good luck - shoot safe! ;)

Rich

1911Tuner

24th May 2006, 17:44

I dunno ambi...Sounds complicated to me. I just break the corner at 45 degrees or so and swipe it along a smooth mill file until the radius comes up...then go over it with a stone and check it with a gauge until it's about right. Not precise, but it doesn't have to be +/- .005 inch.

In a 5-inch gun, if you use a 16 pound recoil spring...a 23 pound mainspring...and a .060-.070 radius, the gun shouldn't short-cycle with
a 200-grain bullet at 775-800 fps. Ejection won't be very lively, but it'll cycle.
Hardball or the equivalent shouldn't be a problem at all.

Hersh

24th May 2006, 21:10

So, this is what one gets, if he does not want to give you inaccurate information, and wants to be very precise? OK, you clever minds, here is how the stop should be filed.

Thanks John ... it seems a lot simpler after seeing a pic. It looks as if you've just barely broken the edge.

Hersh

ttaps

27th May 2006, 10:44

sirs, just wanna ask if using this kind of fpstop configuration could affect the cyclic rate / shooting speed? doeS it create more wear to the hammer pin?
just askin :)

ambidextrous1

27th May 2006, 12:37

I can comment on some of your questions.

On my first trip to the range with the 'trick' FP stop, I encountered a shooter with a 1911A1. I let him shoot my Springfield Ultra Compact with alloy frame and the new FP stop. I didn't fish for compliments, and waited.

After firing two magazines, said it felt good, and he was able to return the sights to the target quicker after each shot.

Based on this 'sample of one', I'd say the FP stop addition offers the promise of faster firing of aimed shots.

Although my gun was lighter than his and had a shorter sighting radius, my "test market responder" thought my gun was easier to handle.

Speculation: I expect hammer wear to be minimal - but I know where to buy a replacement hammer if that becomes necessary. I'm not going back to the old stop.

John

27th May 2006, 14:37

I do not think that the hammer is going to suffer from this firing pin stop, at least not more than it suffers from a standard one. Maybe if you live it perfectly square, the multiple hits to the same spot of the hammer could eventually cause a breakage, but even with a small radius, that shouldn't be a problem. As for the hammer pin, if the radius is done correctly, it is definitely not going to be an issue. If not, maybe you'll have more pressure put to the one side of the pin than on the other, but unless you are shooting thousands of rounds per year, I do not expect to see any problems.

Johnny, your opinion would be appreciated Sir!

1911Tuner

27th May 2006, 16:03

Howdy John,

I've got a pair of older 1991A1s that I've used for beaters since day one.
One of the first things that I did was to install homemade, small-radius stops.
They're both on their third barrel with one complete rebuild/refitting each.
The hammer and sear pins were replaced during the rebuilds. The hammers are original. The guns have clocked approximately 265,000 rounds collectively, about evenly split. Mostly hardball or equivalent reloads.

Cyclic rate/speed? Sure. Anything that can have an effect on the slide will have an effect. Have I noticed a major difference? Dunno. The guns will cycle as fast as I can trigger'em...and I can trigger'em pretty fast. Damage?
None that I can tell.

Bobcape

27th May 2006, 23:42

I just completed this modification to my newish Kimber Team Match II and shot it today. What a remarkable reduction in felt recoil with the same loads I've been using! Thanks very much for the info! What other modifications do you suggest?

Bob

PS - This is my first post.

John

28th May 2006, 01:04

16 lbs recoil springs, 23 lbs main spring and Colt sear springs!

Oh sorry, these are not modifications, these should be standard.

ttaps

28th May 2006, 11:11

Cyclic rate/speed? Sure. Anything that can have an effect on the slide will have an effect. Have I noticed a major difference? Dunno. The guns will cycle as fast as I can trigger'em...and I can trigger'em pretty fast. Damage?
None that I can tell.[/QUOTE]

thank you commandant john and guru tuner; gonna try it this coming sunday on the range, :D , bet my buddies would be amazed!!

thank you sirs.

1911 rules :)

ambidextrous1

30th May 2006, 14:12

Okay, Ihave installed the EGW FP stop in my Springfield Ultra Compact, with favorable improvement, as previously reported.

When attempting a routinebut rare field strip and cleaning, I found that the slide assembly could not be removed from the frame, but encountered a 'brick wall' when it was about 1/8 inch forward of battery position. After a bit of thinking, I removed the FP stop, and voila! the slide assembly came off without a hitch.

I inspected the stop and frame components for bright marks, without significant clues. The firing pin stop appears to be the offending part, and I'm guessing that it encounters the disconnector or the ejector, preventing removal of the slide assembly.

The FP stop fits below flush with the bottom of the slide, so it is most likely contacting the raised portion of the extractor, which I shall atte4mpt to verify next week.

Has anyone had a similar experience?

1911Tuner

30th May 2006, 15:39

Quote:

>The FP stop fits below flush with the bottom of the slide, so it is most likely contacting the raised portion of the extractor (Disconnect), which I shall attempt to verify next week.
***********************

Yep. The other possible trouble spot is with the ejector...which is why we say that there just ain't no sucha thing as a (guaranteed) drop-in part.

Fit it flush with the bottom of the disconnector rail in the slide and it should be fine.

ambidextrous1

30th May 2006, 19:18

Thanks, Tuner,

I'll get around to it next week, maybe; heck, it'll be months before I field strip the weapon again. :o

1911Tuner

31st May 2006, 09:32

No need to strip it. Use a 6-inch smooth mill file and go at the bottom of the stop slowly. keep it square, and when you start to get a small, shiny line on the rear of the rail, at the junction of rail and stop...you're done. Blow out the filings with compressed air, or flush with spray carb cleaner, wipe/drip dry, re-lube. Good to go in 5 minutes. ;)

ambidextrous1

1st June 2006, 11:42

Tuner, I think you're a bit more facile than most of us. I tend to use a file in the same way I use a paint brush: Everything in the vicinity of my AO gets at least a mild dose of what I'm doing! :scared:

The captive slide is no problem under normal conditions. I'm going to put the corrective action on the 'to do' list; it will rise to the top, (hopefully) combined with other item(s) that are similar. With several projects underway, I have to prioritize.

A side comment on rate of fire: I went to the range yesterday and fired on single and multiple targets; the slide stop modification has significantly increased my rate of controlled & accurate fire! ;)

1911Tuner

1st June 2006, 11:58

ambidextrous said:

> I went to the range yesterday and fired on single and multiple targets; the slide stop modification has significantly increased my rate of controlled & accurate fire!<
***************

Amazin' ain't it? Seems that ol' John Moses really DID know what he was doin' before the really smart guys started modifyin' his design. ;)

You'd be surprised at the number of people who just can't accept what that radius does. Had one nearly start a flame war with me over it, and insisted that the difference was all in my head. Said that...because I believed that it reduced the muzzle flip...my perception had become my reality. :rolleyes:

Ah well. Onward...

ttaps

1st June 2006, 11:59

whew!

no egw firing fpin stop available on my side of the world, have check it from the dealer. facricated one from stainless bar, copied the pictures john posted. hope it will perform and not deform.

gonna try out this sunday.
will have a little fun shoot with the visiting navy seals :)

Pappy

1st June 2006, 14:41

1911Tuner

1st June 2006, 14:46

ttaps...Where you be at, and are you active military?

Jim Clark

2nd June 2006, 21:40

Tuner -

I did one for my SA Ultra Compact.

I shot it & didn't see what the big deal was.

I watched my 15 year old 100lb daughter shoot it.
AND
Watched her shoot my Colt 1991A1 (lawyer gun)

The SA rose straight up without twisting in her hand.
The Colt jumped twice as far & twisted about 30 degrees.

I'm sold! I had faith in ya so I'd ordered 4 :) .
You've never been wrong!

Thanks Again for all the enlightenment.

jim

John

3rd June 2006, 01:30

The SA rose straight up without twisting in her hand.
The Colt jumped twice as far & twisted about 30 degrees.

PRECISELY! Without this stop, the gun jumps twice as much and to the righ. With it, half as much and straight up. I do not know why the twist is eliminated, Johnny could enlighten us on this, but I am sure grateful it does.

Finnfire

3rd June 2006, 06:26

Qestion

Tuner 1911, you said that you made first pieces of firing pin stops all youself.
So, what's the best material one should use on these? Gray cast iron for good gliding?

Finnfire

1911Tuner

3rd June 2006, 07:12

Can't find a way to explain the reduction in torque. Never really thought about it, not bein' one to look a gift horse in the mouth and all...

Finnfire...I used 1018 steel, (cold rolled) and case-hardened it with Kasenit, which tended to deform after a few thousand rounds due to the core softness. Later on, I found a small supply of 4140, and used that for a few. Hardened to about 45 Rc, they pretty well mimicked the original stops.
Then, I lost my access to the equipment to machine and heat-treat the parts...but I had a few spares. Then, George Smith of EGW...bless his little pea-pickin' heart...snuck'em onto the market. Since then, I've been tryin' to convince folks of the benefit that they provide at every opportunity. I've caught a lotta flak from the ones who can't understand it, and refuse to
consider the physics involved...until they actually try one side by side with a
"standard" stop. Even then, some are still convinced that the difference is
all in the perception.

ttaps

3rd June 2006, 08:45

sir tuner

location is in southern philippines, im part of the Armed Forces of the Philippines, the USN here are part of the Visiting Forces Agreement.

tried today the modified firing pin stop (fabricated from stainless bar, copied pics john posted), encountered problem with my gun, hammer follows. put on the original fps the problem the problem vanish. fyi, trigger pull of my gun is weighted at 2.3 pounds.

tried firing one round at a time, observed that that recoil was straight up. using wcc match ball ammo. just couldnt figure out hammer follow problem.
should my sear spring be adjusted? run out of ideas, help :(

1911Tuner

3rd June 2006, 08:56

Can't figure what the firing pin stop would have to do with the hammer following other than the small radius causing it to fall back onto the sear more abruptly than the original..and if that's it, it's a problem anyway and would eventually start to follow with whichever stop you use. An action on a 1911 that breaks at 2.3 pounds is a bit ticklish, and on such guns, it's usually not a matter of "IF the hammer will follow...it's a matter of when.

ttaps

3rd June 2006, 09:40

sir tuner,
cant even think of the connection, but i felt that the recoil was more controllable due it was only vertical.

the hammer follow didnt catch the half cock notch and didnt go full auto :scared: , it just resetted back.

gunno try it with my duty gun it has a much heavier trigger.

ill keep u posted

1911Tuner

3rd June 2006, 10:50

That sounds like a disconnector problem...

jaybo292

3rd June 2006, 11:16

Tuner. Here is two pics of a fps I did. I think I took a little to much off. :o Will it still help? Thanks Jay
http://i49.photobucket.com/albums/f253/jaybo292/FPS2.jpg
http://i49.photobucket.com/albums/f253/jaybo292/FPS1.jpg

wichaka

3rd June 2006, 12:06

That looks like a bit too much. I will try to post the proper radius if Tuner doesnt.

John

3rd June 2006, 12:20

Or the stop's dimensions are not right and it does not fully cock the hammer.

jaybo292

3rd June 2006, 12:21

Thanks Wichaka. I`ve seen the right one. Will the one I did help at all? I just ordered another new one.
I new when I did it that it was to much. I was trying to get it as straight as possible. And before I new it Bam. To much.

Pappy

3rd June 2006, 14:09

Or the stop's dimensions are not right and it does not fully cock the hammer.

Wouldn't the slide's rail cock the hammer regardless? If all else is in spec? Pappy

srt

3rd June 2006, 14:37

this thread has been incredibly informative. thanks for the information everyone!

i plan to give this a try. i have a Kimber Custom Classic, circa 1998, non-series II. can i use a series 70 firing pin stop? i removed my firing pin stop and, i think, it looks like a series 80 part but i dont have a firing pin safety.

thanks
steve

wahsben

3rd June 2006, 16:29

dr2e, It appears you are either trying to focus closer than your cameras lens will allow you to and or you need to use a tripod. Every lens depending on its focal length and quality has a different distance that it can focus at. Most lenses won't focus close enough to give you a large enough image. You need either a macro lens, extension tubes or close up attachments for your lens. All lenses and close up attachments are of different quality depending on the maker, what model they are and the price. Also it is always a good idea to use a tripod especially for close up photography.

1911Tuner

3rd June 2006, 17:24

srt

3rd June 2006, 17:38

Steve,

Your Kimber uses the old standard S-70 type stop.

that is what i thought but since it has an 80 style installed on it now i wanted to be sure.

thanks!!!
steve

1911Tuner

3rd June 2006, 18:07

that is what i thought but since it has an 80 style installed on it now i wanted to be sure.

thanks!!!
steve

Odd. Wonder who put that in the gun...Anyway, as long as the gun is a pre-Series 2, it takes the 70 type stop. But...if you're unsure, order the 80 type.
It'll work in either one.

srt

3rd June 2006, 18:26

Odd. Wonder who put that in the gun...Anyway, as long as the gun is a pre-Series 2, it takes the 70 type stop. But...if you're unsure, order the 80 type.
It'll work in either one.

i purchased my gun brand new, i haven't changed any parts besides springs since i bought it, so i assume Kimber installed it...

i could also be mistaken on the difference between the two stops.
this one is 80 type? (http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=6126&title=1911+AUTO+OVERSIZE+FIRING+PIN+STOP)
and
this is 70 type? (http://www.brownells.com/aspx/ns/store/ProductDetail.aspx?p=19627&title=1911+AUTO+OVERSIZED+FIRING+PIN+STOP)

thanks
steve

1911Tuner

3rd June 2006, 18:31

Interesting. And you're quite sure it doesn't have the Swartz system... :confused:

wahsben

3rd June 2006, 18:40

Tuner, what type stop would I use in the Smith & Wesson model 1911's? Thank you.

srt

3rd June 2006, 19:19

Interesting. And you're quite sure it doesn't have the Swartz system... :confused:

i am quite certain it does not have the swartz system. correct me if i am wrong, if the top end were removed from the frame a pin would protrude up from the frame when i depress the grip safety with the swartz system? additionally, i can install/remove my slide while the grip safety is depressed.

does this help?
http://srtadlock.net/images/kimberParts.jpg

thanks
steve

1911Tuner

3rd June 2006, 19:57

srt...Not a Series 2. Yours will take the Series 70 type stop.

wahsben...The Smith & Wessons take the Series 80 stops. I installed one in a S&W pistol not long ago.

srt

3rd June 2006, 20:27

thanks, 1911Tuner.

steve

John

4th June 2006, 01:19

Wouldn't the slide's rail cock the hammer regardless? If all else is in spec? Pappy

You're right Pappy, I wasn't thinking when I posted that. We have the baptizing of the twins today, and since yesterday night I am running a fever, which is not exactly what I had planned for today. So, I guess my brain cells were on strike when I wrote that.

Tom

4th June 2006, 05:17

So, I guess my brain cells were on strike when I wrote that.
Cells? You mean you still have more than one? I've only got the one that I know of, which makes it easy for me to say that I always give 100% of my effort into anything I do. :)

1911Tuner

4th June 2006, 05:35

Well...speaking from a purely technical standpoint...the center rail doesn't cock the hammer. When the slide surges rearward, the stop slams the hammer back and overcocks it. The hammer bounces off the top of the grip safety and falls back to the cocking rail at the junction of rail and stop...or just slightly forward of that point. This, regardless of which radius is on the stop.

:D

Pappy

4th June 2006, 09:11

wahsben

4th June 2006, 09:18

Thank you 1911 Tuner.

jaybo292

4th June 2006, 10:07

1911Tuner

4th June 2006, 13:38

Johnny, if the stop were to be ground down severely (just enough left to hold firing pin), the middle rail would cock the hammer. Correct? Pappy

Nope. The 1911 doesn't operate smoothly, as some think. It's a pretty rough and tumble, slam/bang affair. I suppose that if the mainspring were heavy enough and the ammo light enough, the slide would push the hammer to full cock and no further...but in operation, the sudden, violent punch of the slide slams the hammer clear back to the grip safety tang before it clears the forward edge of the firing pin stop. The hammer bounces off the GS tang, and hits the center rail as the slide is moving.

Now...a very large radius on the stop, with the bottom edge of the stop
cut to within a few thousandths of the rail may allow the rail to do some of the cocking...but I've never monkeyed around with that, so I can't really say for sure. Might make for an interesting experiment though, if somebody has a stop-action camera.

wichaka

4th June 2006, 21:37

OK, here's the proper radius for the slide stop we're all talkin about.

http://w3.gorge.net/scshields/stop.jpg

srt

4th June 2006, 23:05

OK, here's the proper radius for the slide stop we're all talkin about.

i am no expert gunsmith but that looks like a firing pin stop, not a slide stop, to me... :p

all kidding aside, thanks for the pic. that profile shot really helps.

thanks

John

5th June 2006, 00:56

Buh, Wichaka is mixed up, what you expect? He probably had problems with his Wilson magazines today, so you is mixing the slide stop with the firing pin stop. :p

1911Tuner

5th June 2006, 05:39

It's on account of all the pain he's in from that pointy stick I poked him with. :D

John

5th June 2006, 06:25

Yeah, yeah, I noticed it this morning! LoRL, he deserves it though, incorrigible!

wichaka

5th June 2006, 08:53

Ok ok............yes its a firing pin stop............the day was long, and had just gone chatting with a guy anout a slide stop...........at least I got the STOP part right. :D

Jim Clark

5th June 2006, 10:18

We here in da norf wes has ahr own ways fer makin' shur we's talkin' to dem dat unnerstans. Dee's thangs don't posed to git arroun' to aul dem demokrats.

Great pic just like mine.
jim

Pappy

5th June 2006, 12:25

Nope.... in operation, the sudden, violent punch of the slide slams the hammer clear back to the grip safety tang before it clears the forward edge of the firing pin stop. The hammer bounces off the GS tang, and hits the center rail as the slide is moving.

As I see it now:
1. Hammer strikes FPS and perhaps rebounds some on it's own.
2. Slide whacks hammer which is now floating or not, but whacks it back hard and now hammer is free from slide contact.
3. Hammer now unassisted pivots back to overcock, bounces off GS tang and meets slide rail a little forward of FPS.
Yes???? Pappy

1911Tuner

5th June 2006, 12:37

You have learned well, Pappy Grasshopper... :cool:

Pappy

5th June 2006, 12:46

You have learned well, Pappy Grasshopper... :cool:

Thanks Johnny. You have made my day...Pappy

Jammer Six

5th June 2006, 13:22

Wichaka, I am appalled.

Appalled, I tell you. :lm:

As a fellow Washingtonian, I say that you must keep the difference between the Very Back Thingie and the Main Side Thingie straight!

ttaps

5th June 2006, 20:34

it worked, thanks tuner.

thanks wichaka for the picture. really got the correct fps radius with that one.

:) :) :)

1911Tuner

5th June 2006, 20:42

it worked, thanks tuner.

thanks wichaka for the picture. really got the correct fps radius with that one.

:) :) :)

Worked? As in...delivered the reduced flip as promised? :cool:

Wichaka...I use about that same radius on most Commanders. On 5-inch guns, I get it down really tiny. The guns fairly punch straight back in my hand. Flip is about like a 9mm 1911. I'll see if I can get a good picture later on.

wichaka

6th June 2006, 00:46

I too use a less radius on the full sized. I played with a stock square stop, then changed the radius until I felt some difference. It doesnt take much from the radius I showed........much past that and it starts to recoil a bit different.

Was reading Clawsons book about the change of the radius in 1918, only talks about the ease of racking the slide.........doesnt mention the recoil/handling difference.

The pic shown in Clawsons book for the radius is pretty small. Says it to be .078R.......but the pic looks a bit smaller, I would say down the low .070's to high .060's.......maybe a bad pic.

1911Tuner

6th June 2006, 05:52

Wichaka said:

>Was reading Clawsons book about the change of the radius in 1918, only talks about the ease of racking the slide.........doesnt mention the recoil/handling difference.<

Probably because nobody really noticed. By the time the change in the radius
was in force, the Great War was over, and the pistols weren't used so much any more. The Cavalry remained, but...according to my uncle, who was assigned to the cavalry when he went into the Army after the outbreak of WW2...they were active mainly because of tradition than anything else.
The US had been watching Germany's "Blitzkreig" closely, and they knew that
they would have to wage a fast-moving war against him. They also knew that...in the Pacific Theater against the Japanese...the cavalry would pretty much be useless.
******************

And:
>>The pic shown in Clawsons book for the radius is pretty small. Says it to be .078R.......but the pic looks a bit smaller, I would say down the low .070's to high .060's.......maybe a bad pic.<<

Yep. They varied a bit, which leads me to believe that they were done by hand. Setting up such a small part...even in a fixture...and making a proper radius cut would take more time than a skilled hand with a file and stone.
The early ones were probably machine cut, but it's at least likely that during the rush for production in 1917 and 1918, somebody discovered that hand-cutting could speed things along a bit...which would explain the varying radii.
Not very likely that each individual pistol was checked that closely during the Ordnance Acceptance inspections. Of course, that's just speculation...

Jammer Six

6th June 2006, 21:22

Was reading Clawsons book
Book?

Book?

Walk? Car?

[tail thumping on the floor]

What book? :D

wichaka

6th June 2006, 23:06

I have two of his books. I couldnt afford the definitive book thats now going for 700-900 bucks.

But I got his other lesser known book "Colt 45 Government Models (Commercial Series) I got this one before the great price hike on it, for 45.00. I see it now going for 400-500 bucks

The other book is the earlier version of the 2nd edition that came out a year or two earlier. "Collectors Guide to Colt 45 service Pistols - Models of 1911 and 1911A1"

wichaka

6th June 2006, 23:08

Johnny, now that you mention it........it does look like it was hand done. Stands to reason............if one knows what radius to put on them, it doesnt take very long to do it.

Jammer Six

7th June 2006, 00:12

Thanks, Wichaka.

I WISH I had seven or eight hundred dollars to spend on a book...

1911Tuner

7th June 2006, 05:16

I've got'em both too. I got my Commercial Guide for 35 bucks...just in time, it seems. A few details are a bit sketchy, but overall very good.

jeff1124

7th June 2006, 16:15

Ya weren't joking!1 They were 78.00 and 99.00 on Amazon today!

srt

7th June 2006, 20:30

got my firing pin stop today (ordered 2 in case i screwed it up). was simple enough to get the radius on it, i tried to stop a bit short of 1/16" radius using a 1/8" diameter drill bit as a gauge. i can always take more metal off but i cant put it back. had to shave a bit off the sides to get it to go into the slide but that was no big deal. put my gun back together and everything seems to function properly. slide cycles fine, firing pin throws a pencil across the room when i drop the hammer...all is good. feels a bit harder to rack the slide with the hammer down...with the old stop it feels like i am only pulling on the recoil spring...with the new stop it takes a bit more force to get the slide moving but i cant believe anyone would complain that it is too difficult.

now i need to go shooting...by the time i got the gun back together the local indoor range had closed and my wife had let our daughter take my durango to the movies with her friends.../sigh...and our other vehicle, my wife's mustang, cant get to my favorite shooting spot. i guess i have to wait till tomorrow to try it out.

steve

OD*

7th June 2006, 20:50

Does anyone make the square lower edge FP stops in the pre-Series 80 style, specifically?

I know the 80s type will work, but that's not what I'm looking for.

srt

7th June 2006, 21:02

Does anyone make the square lower edge FP stops in the pre-Series 80 style, specifically?

I know the 80s type will work, but that's not what I'm looking for.

the stops i ordered were series 70.

this one is 80 type (http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=6126&title=1911+AUTO+OVERSIZE+FIRING+PIN+STOP)
and
this is 70 type (http://www.brownells.com/aspx/ns/store/ProductDetail.aspx?p=19627&title=1911+AUTO+OVERSIZED+FIRING+PIN+STOP)

steve

OD*

7th June 2006, 21:07

Well duh, me. :o

I guess I should have looked on EGW BEFORE I posted.

Thanks Steve.

I see Guncrafter Industries offers them also.

1911Tuner

8th June 2006, 07:49

srt

8th June 2006, 09:55

srt...You may have cut the radius too large. A 1/16th bit should match the radius and stand flush with the top and rear edge of the flats at the rear corner of the stop. if you can post a picture, I'll know more.

i thought you were saying a 1/16th radius earlier in the thread. a 1/16th radius is the same as a 1/8th diameter...maybe i missread. anyway, the radius i cut is smaller than the 1/8th drill bit. i am guessing it is somewhere between a 1/32nd radius and a 1/16th radius.

i will try to post a picture but will have to wait til i get home from work. plus, my wife is the wiz with the camera so i will have to get her to take the picture for me.

steve

1911Tuner

8th June 2006, 12:18

Hi srt,

It doesn't work in half diameters like you'd think. Take the non-altered stop and hold the 1/16th drill rod up to the corner of the stop where you want the radius. Align it so that the tangent of the rod is flush with the rear face and the bottom edge, and see how much you'd have to take off the corner only to match the shape of the rod. That's the radius you want. If you've stopped where I think you have, all is not lost. The stop will still work nicely on a Commander-length gun.

srt

8th June 2006, 17:55

ok, i hear what you are saying, however, my understanding is the radius of a circle is one half the diameter of the same circle. a 1/8" diameter rod will have a 1/16" radius. when you said 1/16" radius i interpreted that to mean the same as 1/8" diameter.

don't get me wrong, i am not trying to argue. i am trying to understand what 'radius' means in the context which you are using it. i thought it would mean the same thing as it did from high school geometry but maybe i am just interpreting what you are saying incorrectly.

i plan to post pictures when i get home from work.

thanks
steve

srt

8th June 2006, 18:49

here is my stop shown with a 1/8" and 1/16" drill bit for comparison.
http://srtadlock.net/images/kimberParts2.jpg

thanks
steve

1911Tuner

8th June 2006, 19:59

Howdy srt,

The radius on the stop is good. Looks to be about .070 inch...Outstanding job, by the way. Very well done.

For all who are following this thread...This is the way to radius the bottom of the firing pin stop. Clean and straight.

The confusion is in how we learned it in HS geometry, and the radius of a circle is half-diameter...but when forming a radius on a corner...specifically a split corner as on the FP stop...it's a little different. For one thing, the stop itself is only .130 thick at the center, so we can't cut a full radius without nearly rounding off the entire bottom of the stop.

To form a radius on a corner like this, first the thickness of the stop is split.
Then the distance of the radius measured from the square corner to the distance of the radius. In this case...if we cut it true to print spec... about .075-.080 inch. In order to do that precisely, the stop has to be split, and the equalateral triangle formed by that line and the corner is bisected...the distance measured directly on the line that results from the bisection...and the radius formed by rounding the corner off to that depth.

You can see this mo' betta by laying your small bit as close to flush with the curve of your radius as you can eyeball. It should be a close match.

Clear as mud?

1911Tuner

8th June 2006, 20:12

I just had to come back and look at that one more time. If that was all done freehand, it's about as pretty a piece of work as I've seen. You ever thought about takin' up toolmakin'?

ocharry

8th June 2006, 20:47

1911Tuner

8th June 2006, 20:53

ok boys ,, can anyone e-mail me a copy of jb's original blue print? cuzz i think tunner is talking about the hypotenus of the triangle, man am i fuzzed now!! i would like to see what size the radius is called for on the print please

ocharry@hughes.net

The print calls for an .078 inch radius...(5/64ths)...and you're correct. When the equalateral triangle is bisected, it forms two right triangles...mirrored..and the bisecting line is the hypoteneuse for both...or "C" in Pythagoreanspeak. :D

The radius on the modified stop...as requested by the limp-wrist conscripts who couldn't grip the slide hard enough to cock the hammer...was 7/32nds
on the print.

ocharry

8th June 2006, 21:05

thanks tuner,,,cuzz i was gittin skeeerd i messed one of these things up,,, this is great to have this kind of know how right at my fingertips

srt

8th June 2006, 21:22

I just had to come back and look at that one more time. If that was all done freehand, it's about as pretty a piece of work as I've seen. You ever thought about takin' up toolmakin'?

thanks, man. yes, it was done free hand with wetstones.

i have done my fair share of working with my hands. i spent a few years making selfbows, tried my hand at making knives, made jewelry for a while, and most of my youth was spent drawing and sculpting.

steve

Tom

8th June 2006, 21:26

When the equalateral triangle is bisected, it forms two right triangles...mirrored..and the bisecting line is the hypoteneuse for both...or "C" in Pythagoreanspeak. :D
You sure about that? Wouldn't the bisecting line form one of the two sides that make up the right angle, making it either A or B?

OD*

8th June 2006, 21:35

thanks, man. yes, it was done free hand with wetstones.

i have done my fair share of working with my hands. i spent a few years making selfbows, tried my hand at making knives, made jewelry for a while, and most of my youth was spent drawing and sculpting.

steve
Fine job Steve, it looks great.

wichaka

8th June 2006, 22:17

The distance of the radius measured from the square corner to the distance of the radius??????

.......and the equalateral triangle formed by that line and the corner is bisected...the distance measured directly on the line that results from the bisection...and the radius formed by rounding the corner off to that depth???

......hypotenus of the triangle?????

When the equalateral triangle is bisected, it forms two right triangles...mirrored..and the bisecting line is the hypoteneuse for both...or "C" in Pythagoreanspeak???????

Wouldn't the bisecting line form one of the two sides that make up the right angle, making it either A or B??????

wichaka raises hand;

May I be excused, my brain is full! :D

John

9th June 2006, 01:10

Wichaka, don't pay attention to Tom. When they talked about the hypotenus at school, he was there, but he was asleep.

1911Tuner

9th June 2006, 04:11

Tom...Wichaka...You're absolutely correct! Apparently I was the one asleep, or lookin' at it sideways skewed my perspective. :rolleyes: :D

Sorry 'bout that kids. For the record, I'm back on the steroids again...so I plea temporary insanity for the next two weeks. :o

Gawd...

jeff1124

9th June 2006, 04:44

The important thing is that SRT did a good job. Pythagorus lived B.C. ( before computers). "Why don't we all just try to get along?" Rodney King ( I don't know what his theorum was, "try not to get busted" maybe.

John

9th June 2006, 05:27

I do remember Pythagoras theorem, but as long as my 1911 behaves, I'd rather forget it.

OD*

9th June 2006, 06:48

It's all Greek to me.

John

9th June 2006, 06:51

:lm:

Pappy

9th June 2006, 09:32

Thought I understood,
but then.......
and then.......
Folks, I am befuddled!
A good line sketch would help. HELP!!!
P.S. HELP!!!!!!!!
Pappy (I think).

Jerry Keefer

9th June 2006, 11:51

Pappy;
Don't dispare.
This has gone "far" off the charts in complexity... The "radius" you chose is merely the amount you wish to lower the fulcrum point on the hammer. Adjust according to your individual application. The lower the point of contact on the hammer face, the more resistance. It is a very applicable concept to precision bullseye guns. It increases the resistance against the rearward movement of the slide, and retards the unlocking moment, which in turn enhances accuacy, which is the ultimate goal in B/E. There are other things, which in aggragate, with the stop aid in this process. On bullseye guns, angles are cut at specific locations on the stop, to further take advantage of the concept and enhance function, but that is a long story for another time... for the average "joe", the stop pictured previously is more than adquate... One thing I might add that I haven't seen mentioned here in regard to the use of this stop: The hammer face should be squared, radiused and highly polished; excessive over cock eliminated; and the bottom of the stop angled and polished to prevent undue drag/wear on the hammer face..

Good Luck

Jerry

OD*

9th June 2006, 15:21

Excellent, "to the point" post Jerry, thank you.

1911Tuner

9th June 2006, 16:39

Yes...for sure. The descriptions above were for visualization...for those who couldn't get their heads wrapped around it. It's really a simple matter of
cutting a light bevel on the corner, and rounding it off. The actual radius isn't that critical, as long as it's straight. Even the bevel will do.

Squaring off the contact face of the hammer is taking it a step further in order to insure even loading of the pins under the higher stresses of cocking it against the reduced leverage.

One word on the operation to reduce overcocking to a minimum though...

Don't read that as facing the hammer off to just allow it to cock far enough to catch the hooks. It's done so that, when the hammer rebounds off the top of the grip safety and falls back to the center/cocking rail in the slide, it doesn't have so far to fall back onto the hooks, and is kinder and gentler
with a finely-honed sear and hammer...aka "Trigger Job." If you go too far with it, The hammer won't be stopped on the center rail, and will fall directly onto the hooks under a full head of steam...which isn't conducive to a long and happy life for the sear.

So guys...don't grab a file and start takin' metal off the face of the hammer without making sure to provide a little drop from the rail onto the sear, or you'll be replacing things shortly. I had two such pistols on the bench not too long ago because the owners got hold of Ken Hallock's little paperback and did the deed. Seems that Ken failed to explain it completely, and they
cut so much off the hammer that it would just reach full cock when hand-cycled. Either they misread it, or they simply went too far. Either way, they both had to replace hammers and sears.

srt

9th June 2006, 23:32

i finally shot my gun this evening. the difference was amazing. recoil felt like it was straight back and muzzle flip seems to be all but gone. my spent cases were landing about 4-6 feet from me. i am very pleased. thanks for this tip!!!

i wonder if it would be worth using my second stop and trying a smaller radius?

steve

1911Tuner

10th June 2006, 11:12

srt pondered:

>I wonder if it would be worth using my second stop and trying a smaller radius?<
**************

Sure. I've used'em as small as .050 inch. As long as it isn't a sharp corner and is cut straight. Possibility of short recoil in some few pistols if the mainspring and recoil spring are brand new. Should clear up in the first 50-100 rounds though...

.45FMJoe

10th June 2006, 21:08

Here is the FP stop from Colt's serial number 61,2xx.

http://mysite.verizon.net/resreu7d/sitebuildercontent/sitebuilderpictures/usgim1911fp3.jpg

Just in case anyone wants a picture of an original as kind of a template :)

1911Tuner

11th June 2006, 06:18

DAYUMMM! A 5-number gun and original too? You need to go play the Powerball, lad.

The stop looks to be in good condition, albeit a little worn. If you check the radius with an accurate gauge, you'll probaby find that it's a bit larger than
.078 inch. It's pretty close to the same that I've seen on older P-35s. May have been one that received one that was hand-cut.

Now...How 'bout a shot of the whole pistol...

1911Tuner

11th June 2006, 08:56

Okay...Went and dealt with the 'Roid Tremors and things have subsided for the moment, so I can post again without writing in an alien language. :rolleyes:

The thing to keep in mind is that the exact spec/dimension for the radius isn't written in stone. You can vary it to suit your tastes and/or tune it to the individual gun. I've pretty well settled on about .060 inch on my five-inch range beaters and carry guns, and .075 or so for Commander-length pistols. .090-.100 seems to work well with what few shorties that I've messed with, but you can go even smaller in most cases. I'd suggest for the 5-inch Deltas and other Big 10s to start with a .050 radius. With that dimension, you can use a 25-pound mainspring and get by just fine with a recoil spring in the 18-19 pound range...though some guns may require 20 pounds to provide the buffering effect required.

The essence of fine-tuning is in the experimentation. Ain't this fun? ;)

SOCOM6

16th June 2006, 09:44

I am new to this forum, but found this thread very interesting. This past week I put a new EGW FP Stop in my Springfield TRP and in my fathers Colt 1991, WOW!! I could not believe the difference that it made, I am a big guy so recoil never really bothered me, but after changing this one part my follow up shots are much quicker!!! My father also noticed a big improvement!! This was the best 15 bucks I have ever spent on a gun, Thanks for posting the info on how to Tuner!! You made it easy for me to figure it out! Now I need to sit down and read all the other posts on maintenance and gunsmithing! Keep posting the great information!

John

16th June 2006, 10:43

Another happy customer!!! :D :)

1911Tuner

16th June 2006, 10:50

Waitin' for the royalties to start rollin' in... :D

John

16th June 2006, 10:57

Hey Johnny, what would you suggest for a 9mm 5" pistol?

1911Tuner

16th June 2006, 12:07

Honestly, John...I can't say. I've probably seen fewer than a dozen pistols in that caliber over the years, and have only had occasion to work on two. They're just not very common in these parts. I'd say that about the same radius that works out on a Commander would do though. I've seen older P-35s with what appeared to be about .100 inch or maybe a little less. Of course, the High Power's slide is a little lighter...I'm fairly sure...than the 1911's, so that would doubtless be a factor too.

In .38 Super, you'll probably be good to go with whatever works with .45s, but the main thing to look at is that George provided us with the means to trial and error/fine tune the stop's radius. Pure, simple marketing genius, IMO. :cool: