Link Question

[heat151]

I think I may need a longer link.
I have two Colt Commanders.

With Commander #1 in full lock-up, with the hammer down (against the fp stop) I remove the barrel bushing and press the muzzle as far up towards the top of the slide as possible. The barrel hood is now at an angle, tilted up, but the entire barrel itself does not move upwards towards the top of the slide. There is a slight gap around the top of the entire barrel hood, as it does not fit closely to the slide

With Commander #2 in full lock-up, with the hammer down, I remove the barrel bushing and press the muzzle as far up towards the top of the slide as possible. The barrel hood is vertical with no noticeable angle, and it appears that the entire barrel cannot move any further upwards towards the top of the slide. There is hardly any gap between around the top of the entire barrel hood, fitting much closer to the slide.

Both pistols are shooting just fine, but I'm not sure that Commander #1 is within spec somewhere. Would a longer link adjust this situation?

I'm afraid I don't have a camers for photo's so I apologize for that in advance.
Digital calipers are all I currently have for any measurements desired.

Thank You for any and all replies.

[log man]

Quite frankly your "test" doesn't really make any sense as to correct link length.

LOG

[niemi24s]

I'm not familiar with the "remove the bushing and push the muzzle up" test you refer to but, although it may have some merit, it seems trying to assess link length by fiddling with the muzzle is somehow flawed.

A gun with a non-hard fitted barrel needs a longer link (has too short of a link) when the vertical engagement of the radial locking lugs on the barrel and slide is inadequate. The average GI M1911A1 has about 0.039" of engagement, but most folks think 0.042 to 0.045" is adequate.

Q1: What size links are installed in gun #1 and gun #2?

Q2: How much vertical engagement is present in gun #1 and gun #2?

[heat151]

Sorry for the long wait. Let me give some background.

This started as checking for barrel spring and I found that Commander #1 has some give when in battery/hammer cocked. Commander #2 does not.
I then noticed the gap in #1 compared to #2.
By taking the bushing off, I wanted to see what the barrel would do. Since #1 has barrel spring and #2 does not,then perhaps barrel #1 is being "displaced" by a short link, causing the barrel spring and gap? Or am I way off into outer space?
Neimi, how would I get the measurements you are asking for? Sorry, I'm very new to the 1911 build. :confused:

[log man]

Ideally the barrel lower lug feet will sit on the slide stop pin and give a solid lock-up, in which case the link has nothing to do with the barrels rise, which is the job of the cam surface of the lower lug. And the link is there only for the purpose of pulling the barrel down during recoil before the lower lug hits the VIS (vertical impact surface). This takes place in the first .250" of rearward travel.

When a barrel rides the link into battery which I believe yours is, the link cannot hold the barrel up firmly because it, the link goes past center in battery. This means that as the barrel is being pushed by the slide and guided by the swing or arc of the link it reaches a point where it is as high as it can go and then to our disappointment continues on and drops a little when in battery. So a longer link can't fix this condition. I've noticed in several like yours the barrel hood is much firmer when a round is in the chamber. A longer link has the detrimental potential to negatively affect link-down timing as the barrel's lower lug will hit the VIS before it has cleared the slide with enough safe clearance.

Keep exploring, keep reading and keep asking questions, it's a fun journey.

LOG

[heat151]

Thank You Log Man, your reply clears up the most likely reason as to what's happening.
I just don't see an obvious difference between the two pistols that is causing one to have the barrel spring. The bushings on both fit loose enough to take on and off by hand.
Would the VIS or any other part of the frame do this?

[niemi24s]

. . . how would I get the measurements you are asking for? For the link size, look in Post #40 of the Thread "Function Problem", http://forum.m1911.org/showthread.php?t=58721 . For measuring lug engagement, use this site's Advanced Search Engine to search for "popsicle stick", an implement used to take the measurement.

I'm still not sure what your no-bushing test reveals except that your two guns are not identical in their responses to the test. This no doubt means your two guns are not physically identical. Take comfort in the knowledge there's probably no two identical Commanders anywhere in the known Universe - statistically speaking, that is.

If you want to drive yourself crazy, try swapping parts back & forth between the two guns to see if you can get them to perform the same during your no-bushing test!

Regards

[niemi24s]

This started as checking for barrel spring . . . The "barrel spring" test I'm familiar with is done with the slide off the frame, slide inverted on the bench, barrel & bushing installed in the slide and the barrel in battery position in the slide. When the aft end of the barrel is pushed downward for maximum lug engagement, the bushing should not bind on the muzzle and cause the aft end of the barrel to lift back up when the downward pressure is removed.

Your barrel spring check sounds a lot different.

[log man]

Thank You Log Man, your reply clears up the most likely reason as to what's happening.
I just don't see an obvious difference between the two pistols that is causing one to have the barrel spring. The bushings on both fit loose enough to take on and off by hand.
Would the VIS or any other part of the frame do this?
The VIS is the vertical back wall of the pocket in the frame that the lower barrel lug fits in. When the barrel is in battery it is forward and isn't touching the VIS.

It takes a while to get the terminology right, barrel spring is used in reference to a too tight a bushing that won't let the barrel go into lock-up without undue pressure on the barrel causing it to spring or flex slightly.

Mostly it sounds as if the hood is fitted looser on one than the other. With the guns fully assembled how much space is there between the end of the hood and the breech face? A well fitted gun will not close completely when a thin piece of paper is placed in this position. How much thickness does it take to keep the barrel from going into battery in each gun? Pull the slide back and insert a feeler gauge or narrow strips of paper to find this out.

LOG

[heat151]

Hey Niemi,guess what, no barrel spring doing your test.
My test sounds like I got very confused...yup, that must be it.

Log Man, Thank You for the information. Since riding the link is not good,
what bad things can I expect to happen and how can this get fixed?

I thank both of you for your time and assistance!

[log man]

There's nothing actually wrong with riding the link, it's just not as accurate of a way for the 1911 to operate. Colt has put out many that ride the link and few that don't. It's much easier to mass produce as less fitting is required. For your guns, enjoy them and if you'd like more accuracy fit or have a new barrel fitted.

LOG

[niemi24s]

Since riding the link is not good, . . .Don't get carried away by semantics. "Not good" implies "bad", and riding the link is not bad (or good).

The average GI M1911A1 rides the link all the way into battery.

On the other hand, a 1911 with a gunsmith fitted oversize barrel with its lower lugs cut so they support the barrel in battery does not ride the link all the way into battery.

There is, therefore, nothing "wrong" with your gun just because it's barrel is supported by the link (instead of its lower lugs) when in battery.

The primary disadvantage of a link rider is, as Log Man pointed out, the utmost in accuracy will not be realized because the back of the barrel is not locked up tightly. Only a hard-fit, oversized lug barrel can be locked up tightly in battery and attain the utmost in possible accuracy.

Cheers

P.S.: Dang it, Log Man posted while I was still poking away - and said it better with lots less words! :)

[auto45]

Won't you break links that way?

[log man]

Won't you break links that way?
Links break most often when they stop the barrel at link-down without the lower lug hitting the VIS. A timing problem not related to riding the link.

LOG

[niemi24s]

Won't you break links that way?The link is in compression when going to battery in a link riding gun, and I don't think it's possible for a 1911 to compress it enough to do it any real harm - much less break it.

During linkdown, however, the link will be in tension until either the VIS or bed is hit first and, as Log Man mentioned, if the bed gets hit first the link will eventually break. This is because link tension can only be relieved if the VIS is hit first - and because the link's much, much more apt to deform or break in tension than in compression.

[niemi24s]

And (to finish the scenario of the broken link) when the link, in tension, can no longer withstand the stress of halting the barrel's aftward motion (because the VIS is never hit or never hit first) it will no doubt fail during linkdown after a firing - while it is in tension (the straw that broke the camel's back, so to speak).

The overstressed link will probably break at the outer periphery of either its large or small hole, and this break will probably not prevent the gun from going to battery with the next round. Here's where it gets scary!

When that next round is fired and the slide and barrel (still vertically engaged) begin moving aftward on the slide, the broken link is unable to pull the barrel all (or perhaps any) of the way down out of vertical locking lug engagement with the slide. Then, when the barrel's lower standing lugs contact the VIS, the standing lugs try to stop the aftward motion of both the barrel and the slide (still vertically engaged). The mass of the slide & bushing is about 4X that of the barrel, so . . .

. . .the result is, as I understand it, the standing lugs can get pulled away from the bottom of the barrel and some (perhaps considerable) damage occurs to the slide's locking lugs.

I must confess I have never seen a broken link or the results of one. What's above is what I've picked up from sniffing around on this Forum for a few years.

Did I get it sniffed out right?

Cheers

[auto45]

Did I get it sniffed out right

Sounds plausable/possible depending on when and how it breaks.

I've broken one link and it jammed the gun up solid, about 1/4-1/2" out of battery...and I mean solid. :)

[niemi24s]

I've broken one link . . .Where did yours break?

[auto45]

I believe, if I remember, it snapped around the slidestop.

Not sure exactly where the break was, top /bottom, etc.

[niemi24s]

Hi Auto45:I've broken one link and it jammed the gun up solid, about 1/4-1/2" out of battery...and I mean solid. :) Got to wondering if maybe it was more likely a broken link would jam up the gun rather than allowing it to return to battery with another cartidge in the chamber. After squinting at my gun and the sectional views in the blueprints came up with this for better "seeing": http://i129.photobucket.com/albums/p232/niemi24s/P08B240001c.jpg There's precious little space around the link, so I'm guessing it may be more likely to jam up the gun - and chambering the next round (all set to ruin the barrel) might less likely. Maybe.

As you said, it all probably depends on where, when & how the link breaks. But, it seems to me at least, the link would have to break after the barrel's linked down and failed to make VIS contact (until after the link breaks)

Regards

[auto45]

But, it seems to me at least, the link would have to break after the barrel's linked down and failed to make VIS contact (until after the link breaks)

No doubt it was weakened, ready to break by the failure to make vis contact.

Then, snapped completely?

One thing for sure, the guns "locked", so you better have another gun. It's not like replacing an extractor, slidestop, etc. It's something you don't want to happen.

I think you can shoot a fair amount of rounds with a poor barrel fit though. :D

[niemi24s]

I think you can shoot a fair amount of rounds with a poor barrel fit though. :D That prompts the question "How many rounds of X ammo does it take to make the link fail?" Probably too many variables to ever figure out. Best deal is avoid the whole fiasco by taking care. :)

Cheers