Help needed for irregular primer strike

[Iceman]

OK, this is the problem...I recently installed a bushing comp on my SA Loaded Target in 9mm. Recoil spring is Wollf 14# matching factory weight with Nowlin 19.5 lb. hammer/main spring and Nowlin matching HD firing pin spring. Before installing the comp, there are no reliability problem at all. But now 1 in about every 25 rounds or so, I would get a weak primer strike causing the cartridge not firing leaving a weak indentation in the primer. This has happened twice so far once today in my hand and once couple of weeks ago with another shooter. And the funny thing is, it's always two in a roll. Please see the photo:

http://www.actionsupplies.biz/images/pix/Gun%20023.jpg

The left two is the cartridge that did not fire after the incident and the other 4 are the fired casings. Just in case you wonde, the slightly off-centre primer strike is always there. I have checked the cartridge specs and found the two that did not fire would not pass the headspace guage BUT will chamber and other rounds with similar specs still did fire before. The gun is also recently cleaned and has only about 50 rounds through it after cleaning.

This is not a real problem as yet but sort of affected my confidence when competing weekly matches today already...was doing so well until this happened and then just rushing shots after that...

Any thoughts? :( Any help and/or input would be greatly apprecaited especially if they come from Tuner!!! :D

[Iceman]

BTW, I also just cleaned the firing pin channel as well and there doesn't seem to have any debris apart from the usual burnt powder residues in it....

[1911Tuner]

Howdy Iceman,

Well..You eliminated the obvious when you checked the tunnel for blockage.
Kudos!

Have you checked to see if the firing pin travels freely? If your pistol has the standard ILS firing pin, it may be too light. Try a steel pin. I'd also suggest upping the mainspring to 21 pounds. If you've swapped out the hammer for a
lighteer one...or one of those skeletonized "speed" hammers...that may be your bug.

Then, there's always the possibility of hard or soft primers. Pretty rare to find
that much variation within one lot, but it can happen.

The off-center strike is a barrel fit issue that normally doesn't cause too much problem unless the strike is more than half the pin diameter from center.
With very hard primers...such as CCIs Mil-Spec line, you may get erratic ignition...hangfires...or misfires. You can determine whether it hits high or low by marking the top of the case with a sharpie marker and looking to see which direction it's off relative to the index.

[Ken Grant]

Once in a while,I have had several light primer strikes on one of my 1911's.
I found out that the pistol sometimes would not be all the way into battery and I would have a misfire. The hammer fall would drive it into battery and by re-cocking it,it would fire the next time.
Kinda hard to spot if you are not looking for it as the slide was barely sticking past the frame.
I found that it was happening often but not enough to cause a misfire all the time( maybe 2 misfires out of a 100 rds)
I had to look at the rear of the slide after each shot to find out what was going on.

[Iceman]

Howdy Iceman,

Well..You eliminated the obvious when you checked the tunnel for blockage.
Kudos!

Have you checked to see if the firing pin travels freely? If your pistol has the standard ILS firing pin, it may be too light. Try a steel pin. I'd also suggest upping the mainspring to 21 pounds. If you've swapped out the hammer for a
lighteer one...or one of those skeletonized "speed" hammers...that may be your bug.

Then, there's always the possibility of hard or soft primers. Pretty rare to find
that much variation within one lot, but it can happen.

The off-center strike is a barrel fit issue that normally doesn't cause too much problem unless the strike is more than half the pin diameter from center.
With very hard primers...such as CCIs Mil-Spec line, you may get erratic ignition...hangfires...or misfires. You can determine whether it hits high or low by marking the top of the case with a sharpie marker and looking to see which direction it's off relative to the index.

Hey buddy!

Yes, the firing pin seems to be travelling freely and I did swap out the original firing pin for a Wilson COmbat steel ones...and using original hammer.

I am using CCI small pistol primers as I found Winchester ones were too soft...so may be the it is a bit of a cartridge issue...I have sorted out the cartridges that won't go through the Headspace guage and see if that helps...

From what you see in the photos, is that sort of cause of concern? It does seems to be about one diemeter out from the centre...is it worthwhile for me to try to re-fit to bring it to centre? I guess to eliminate all problems, may be it is worthwhile I suppose...so what do I do after finding out it's striking high or low? I haven't done a barrel fit before... :o

[Iceman]

Once in a while,I have had several light primer strikes on one of my 1911's.
I found out that the pistol sometimes would not be all the way into battery and I would have a misfire. The hammer fall would drive it into battery and by re-cocking it,it would fire the next time.
Kinda hard to spot if you are not looking for it as the slide was barely sticking past the frame.
I found that it was happening often but not enough to cause a misfire all the time( maybe 2 misfires out of a 100 rds)
I had to look at the rear of the slide after each shot to find out what was going on.

Hi,

Thanks for that...I think you may reinforced my original suspecision that when chambering cartridges that didn't pass the headspace guage, it may have amplified the other minor problems and causing it to hangfire/misfire. I have sorted my ammo's again and see if that helps...cheers! :)

[Gammon]

If the ammo will chamber, it should fire. I would return to the stock main spring which I believe is 23 lbs.

[Hawkmoon]

If the ammo will chamber, it should fire. I would return to the stock main spring which I believe is 23 lbs.
My thought, also.

When something doesn't work after making changes but it did before, Occam's Razor suggests looking first at the thing you changed as the cause of the problem. The bushing shouldn't do it, but you also installed a weaker hammer spring combined with a stronger firing pin spring (which works against the hammer). I would try using a stock 23-pound hammer spring (mainspring) and see if that makes a difference. If so and you feel you really NEED a lighter spring, Wolff offers a calibration pack with one each in 19, 20 and 21 pound weights. You could get the kit, try the 21 pound, and if that still works try dropping down to the 20.

I would not go less than 20 pounds in any event.

[Iceman]

My thought, also.

When something doesn't work after making changes but it did before, Occam's Razor suggests looking first at the thing you changed as the cause of the problem. The bushing shouldn't do it, but you also installed a weaker hammer spring combined with a stronger firing pin spring (which works against the hammer). I would try using a stock 23-pound hammer spring (mainspring) and see if that makes a difference. If so and you feel you really NEED a lighter spring, Wolff offers a calibration pack with one each in 19, 20 and 21 pound weights. You could get the kit, try the 21 pound, and if that still works try dropping down to the 20.

I would not go less than 20 pounds in any event.

Hi, thanks for the comment...

The funny thing is that there was no such problem until the comp is fitted...and because I also changed out the ILS main spring housing and replaced with the Smith & Alexander magwell MSH, it shouldn't cause any interference...I felt the stock 26lb. ILS system is way too heavy for a 1911...but I could try the 21 lb. mainspring but I sort of like the current 2lb trigger pull...

Could the spring of the firing pin causing rebound problems because the slide is now heavier?

[1911Tuner]

Okay, Iceman. Looks like you've seen to all the obvious causes. See Ken Grant's post and make sure the gun is going to full battery. ALthough it shouldn't allow the hammer to fall when it's out as little as .050 inch, some will, even with the slide further out than that.

There could be an issue with the 21 pound mainspring and the extra power FP spring...but it would likely be more consistent. The 21 poind mainspring should be enough, but it depends on how stiff the FP spring is.

Going from a 21# rating to a 23 on the mainspring will have very little effect on your trigger pull...maybe 4-5 ounces.

[Iceman]

Okay, Iceman. Looks like you've seen to all the obvious causes. See Ken Grant's post and make sure the gun is going to full battery. ALthough it shouldn't allow the hammer to fall when it's out as little as .050 inch, some will, even with the slide further out than that.

There could be an issue with the 21 pound mainspring and the extra power FP spring...but it would likely be more consistent. The 21 poind mainspring should be enough, but it depends on how stiff the FP spring is.

Going from a 21# rating to a 23 on the mainspring will have very little effect on your trigger pull...maybe 4-5 ounces.

OK, sounds like might be time to pull the old girl apart again! :scared: I am sort of lazy these days... :o So you think this may be as simple as the out of spec ammo? Which sorta fall into Ken's post?

[1911Tuner]

Could be ammo..Could be a little taper in the forward third of the chamber...Could even be a little too much tension on the extractor, or a bit too much wall exposure above the guide block. Hard to say until ya really start lookin' close.

[Iceman]

Could be ammo..Could be a little taper in the forward third of the chamber...Could even be a little too much tension on the extractor, or a bit too much wall exposure above the guide block. Hard to say until ya really start lookin' close.

Hmmm...now you really getting me worried...ok, I'll check the ammo this Sunday first and if this happened again, then we will try to break this thing down and see what's going on...

Thanks for all the input... :)

[1911Tuner]

Hmmm...now you really getting me worried...ok, I'll check the ammo this Sunday first and if this happened again, then we will try to break this thing down and see what's going on...

Thanks for all the input... :)

Nothin' to fret over, Ice...Everything I mentioned is about a 5-minute fix individually.

[Hawkmoon]

There could be an issue with the 21 pound mainspring and the extra power FP spring...but it would likely be more consistent. The 21 poind mainspring should be enough, but it depends on how stiff the FP spring is.

But he doesn't have a 21-pound mainspring -- he dropped all the way down to a Nowlin 19.5-pound mainspring ... and a heavy firing pin spring at the same time.

[1911Tuner]

But he doesn't have a 21-pound mainspring -- he dropped all the way down to a Nowlin 19.5-pound mainspring ... and a heavy firing pin spring at the same time.


Ahhhhh...I see that now. I had it in my mind that he ad a 21 pounder in it.
Yeah. I'd drop back to a standard FP spring and up the mainspring at least 2 pounds. For what it's worth, I never use anything lower than 23# on any of mine. So, with a 23# unit, we're talkin' maybe a half-pound increase in trigger pull...maybe.

[Iceman]

Ahhhhh...I see that now. I had it in my mind that he ad a 21 pounder in it.
Yeah. I'd drop back to a standard FP spring and up the mainspring at least 2 pounds. For what it's worth, I never use anything lower than 23# on any of mine. So, with a 23# unit, we're talkin' maybe a half-pound increase in trigger pull...maybe.

Aha! Ok, so I shouldn't even feel much difference with 1/2 lb increase in trigger pull...

Now with the other things, what's the wall exposure above guide block?

And also how do I fix the barrel alignment after finding out it's hitting high or low?

Thanks Tuner! ;)

[1911Tuner]

Aha! Ok, so I shouldn't even feel much difference with 1/2 lb increase in trigger pull...

Now with the other things, what's the wall exposure above guide block?

And also how do I fix the barrel alignment after finding out it's hitting high or low?

Thanks Tuner! ;)

1...Tensioning wall of the extractor...The area behind the claw that applies force to the case rim.

2...Install and fit a new barrel. (It may hitting left or right. Check the clearance on the sies of the hood to see if it's fairly even on both sides.)

3...Mighty welcome, sir!

[Iceman]

1...Tensioning wall of the extractor...The area behind the claw that applies force to the case rim.

2...Install and fit a new barrel. (It may hitting left or right. Check the clearance on the sies of the hood to see if it's fairly even on both sides.)

3...Mighty welcome, sir!

Hehehe...mighty Johnny comes through again! :)

But sorry for my ignorance, what the 'sies' of the hood? :confused: So what if it's hitting high or low? So this is the same procedure for the existing barrel? As long as the bushing comp fits the barrel fine, it shouldn't alter the barrel angle, right?

Thanks buddy!

[Hawkmoon]

But sorry for my ignorance, what the 'sies' of the hood? :confused:
Pardon me for butting in, but I suspect a typographical error. I think Tuner meant to type "sides" of the hood. In other words, be certain that the barrel hood is centered in the frame, not pushed to one side because the opposite side is an interference fit in the slide.

[1911Tuner]

Hehehe...mighty Johnny comes through again! :)

But sorry for my ignorance, what the 'sies' of the hood? :confused: So what if it's hitting high or low? So this is the same procedure for the existing barrel? As long as the bushing comp fits the barrel fine, it shouldn't alter the barrel angle, right?

Thanks buddy!

SIDES...of the hood, dang fingers won't hit the right keys. :D

Clearance between the sides of the barrel hood and the slide recess it fits into.

Barrel angle is primarily determined by how far up into the slide it sits when in battery. The bushing has a small effect on the final angle by either lifting the front of the barrel higher...tight fit...or allowing it to drop lower...loose fit.
But, this part of it won't have any practical effect on causing or correcting an off-center pin strike. It's mostly the chamber end's location relative to the slide axis that determines that. Other factors are the depth of the slots between barrel lugs, and the height of the slide lugs...and whether they
hit in the lug slots and locate the chamber face on the slide.

There shouldn't be a lateral angle. If the SIDES of the hood are badly fitted, with one hitting and one clear, it will cause a lateral shift..but it shouldn;t be very much.

[Iceman]

Pardon me for butting in, but I suspect a typographical error. I think Tuner meant to type "sides" of the hood. In other words, be certain that the barrel hood is centered in the frame, not pushed to one side because the opposite side is an interference fit in the slide.

ohhh, I see! Thanks for that!

Now what if it's hitting high and low, what problem could that be? I haven't had a chance to take a closer look yet but I thought I might try to understand it all before I take out the scalple! :o

[Iceman]

SIDES...of the hood, dang fingers won't hit the right keys. :D

Clearance between the sides of the barrel hood and the slide recess it fits into.

Barrel angle is primarily determined by how far up into the slide it sits when in battery. The bushing has a small effect on the final angle by either lifting the front of the barrel higher...tight fit...or allowing it to drop lower...loose fit.
But, this part of it won't have any practical effect on causing or correcting an off-center pin strike. It's mostly the chamber end's location relative to the slide axis that determines that. Other factors are the depth of the slots between barrel lugs, and the height of the slide lugs...and whether they
hit in the lug slots and locate the chamber face on the slide.

There shouldn't be a lateral angle. If the SIDES of the hood are badly fitted, with one hitting and one clear, it will cause a lateral shift..but it shouldn;t be very much.

I think I am start to understand it now...I think the diagonostic can be helped by the wear marks on the barrel hood? I do see some wear marks on the hood...I'll try to take some close-up shots so you guys can see what's going on...

Thanks again and keep u posted... :)

[Gammon]

I took another look at the primers and something came to mind. I see primer flow around the firing pin mark. If you get enough of this it is possible for some of the primer to be shaved of by the firing pin hole in the breech. These shavings can interfere with the function of the firing pin. This happened to me once in a S&W 6906 with hot loads.

PS I would lose the bushing comp. A tungsten guide rod will give about as much recoil control without adding length to the barrel.

[Iceman]

I took another look at the primers and something came to mind. I see primer flow around the firing pin mark. If you get enough of this it is possible for some of the primer to be shaved of by the firing pin hole in the breech. These shavings can interfere with the function of the firing pin. This happened to me once in a S&W 6906 with hot loads.

PS I would lose the bushing comp. A tungsten guide rod will give about as much recoil control without adding length to the barrel.

Hi, thanks for the comment...so you think the load may be too hot? If I want to keep the comp, do you think may be change the recoil spring to 16# keeping the same ammo?

[Gammon]

I'm not sure that the load is too hot, but cratering aroung the firing pin hole can be a sign of excessive pressure. I would try another, softer load. I would still dump the comp and add a heavy guide rod. Recoil spring weight is another matter altogether dealt with in several threads in the Gunsmithing section.