barrel link broken question

[jimbullet]

So I have a 40 S&W STI DVC which broke its barrel link and so I began to remove the broken link and thinking of replacing it.

 

I have inspected the gun and it does not appear that there has been any other damage in the upper, lower lugs of the barrel and the slide lugs and frame VIS areas which was really fortunate. 

 

I noticed that the barrel link is numbered 3.5 which I thought was strange as I mostly find barrel links are numbered like 1-5. Would I be able to use #3 then?

[jim vaughan]

Insert a 3 and then a 4 link and see which one passes the timing tests. It is possible to buy 3.5 links.

[zzt]

Cheely Custom sells links in half sizes.

[shred]

Dawson used to make the "superlink" in half sizes and it's possible that's what's in your pistol, although it's been decades since they were made, it wouldn't be too surprising if a STI gunsmith had one in a bin somewhere.

 

 

[jimbullet]

thanks, will search for those 3.5's.

 

Also out of curiosity, is it possible for the link to fail due to possibly steady diet of hot loads assuming that it has passed the timing test in the first place?

 

Hot loads I mean say 180gr at 1000 fps average, or perhaps sometimes reaching 1020 fps.

[zzt]

4 hours ago, jimbullet said:

thanks, will search for those 3.5's.

 

Also out of curiosity, is it possible for the link to fail due to possibly steady diet of hot loads assuming that it has passed the timing test in the first place?

 

Hot loads I mean say 180gr at 1000 fps average, or perhaps sometimes reaching 1020 fps.

 

No.  Either it was a defective link, or there is something wrong with the barrel fit.

[jimbullet]

So as an update, I managed to get a 3.5 link, installed it and what I found was the following:

1. Initial hand cycling it was all fine until I point the downwards and the gun is not going into battery (it hasn't dont that before)

2. Tested to feed dummy rounds - racking it real quick, letting the slide go, it will feed

3. Racking and slowing down slightly the slide but not necessarily trying to stall it, it's now showing signs of failing to feed. Previously not doing that as well.

 

I do the test which is push the muzzle against the table and the slide stop lever hanging a bit out to see whether its riding on the link or not and noticed that in this position, the slide stop is not totally loose which now suggest that it is riding the new link. Strangely I did this test years ago and this pistol passed where the slide stop was fairly loose and only tightened when pistol is in full battery.

 

So I am beginning to think that the old link sized 3.5 might have been incorrect (?) and stretched maybe thus passing the test above a year ago? (is this even possible?) So with the above, should I try a link size #4 or #3?

 

I just find it weird when the original link #3.5 on it did not exhibit any failure to feed at all and no binding, which suggest to me that it was properly built but how come changing to the same size link, changes the dynamics? The link that I got though is slightly thinner than the original link but that shouldn't be an issue I thought given the same size of 3.5. 

 

I realise maybe better to get someone to look into it but I'd be keen to understand why and if I can easily remedy to a longer link so that I can compete with it in two weeks time.

[sauza45]

Check the slide stop for wear or bent.

[jimbullet]

2 hours ago, sauza45 said:

Check the slide stop for wear or bent.

Thanks, I've checked it by using both the old slide stop and a spare new one I had and in both instance, same results.

 

I've taken the caliper out as well and measured the barrel link (broken and new) and actually they are both the same width too.

 

 

[zzt]

When in battery, the barrel feet sit on the slide stop pin.  Press down hard on the hood.  If there is any movement at all, the link is too long.  If you cycle the slide by hand and slowly let it go forward, you should feel no bump.  If there is a slight bump just before it goes into battery, one of three things will fix that.    If the barrel feet rest on the slide stop pin 'properly', you can reprofile the ramp up on the feet.  If there is pressure on the feet when on the slide stop pin, your link is too short.  You can elongate the hole a little, until it fits, or go to a #4.  A little loose is better than a little tight.

[jimbullet]

thanks ZZT, I will give that a go

[shred]

It's not uncommon for smiths to open the hole on the link a little to fine tune the fit.

 

[jimbullet]

3 minutes ago, shred said:

It's not uncommon for smiths to open the hole on the link a little to fine tune the fit.

 

good to know but my DIY smithing on doing that may not be up to par so I'll try the #4 first and see (cross fingers it works and just survive decently in the upcoming match)

[zzt]

1 hour ago, jimbullet said:

I'll try the #4 first and see

 

If you get downward movement when pressing on the hood with a 4, elongate the 3.5.  Just use a rat tail file and elongate the hole away from the barrel.  Easy Pesy.

[jpl]

At link down is the barrel contacting the VIS?  If not it is stopping on the link and that condition will break links, guaranteed!

 

Paint the back of the feet with a marker and put the top end on the frame without the recoil system.  Move the slide to the rear and tap the muzzle a few times with a plastic or leather hammer.  Remove the top end and look at the VIS and the back of the barrel feet for contact marks.  If you don's see any the barrel is not moving far enough to the rear and is incorrectly fit.

[jimbullet]

I uncovered that the failure to go to battery is more or less more consistent when the gun is upside down. 

[jimbullet]

 

[jim vaughan]

The difference is most probably due to the friction between the top of the barrel chamber and the underside of the slide. Test it using a full slide stoke or dummy rounds and I think you will find that all is good.

[yigal]

4 hours ago, jim vaughan said:

The difference is most probably due to the friction between the top of the barrel chamber and the underside of the slide. Test it using a full slide stoke or dummy rounds and I think you will find that all is good.

If you stood on your head and tried it then everything would work fine.

[392heminut]

In my 40+ years of working on 1911s and 2011s I can't remember one time of ever trying to cycle one of them upside down.

[jimbullet]

Well there is always the first time. You never know if you have to rollover to shoot.  jerry miculek shot revolvers upside down in a demonstration shoot years ago. 

[yigal]

54 minutes ago, jimbullet said:

Well there is always the first time. You never know if you have to rollover to shoot.  jerry miculek shot revolvers upside down in a demonstration shoot years ago. 

You should have seen the movie Leon

[CHA-LEE]

I hate to say it buddy but the STI DVC Series of guns usually had HORRID barrel fits. I have seen a bunch of them where the slide lock pin hole in the barrel link was hogged out to a preposterous size which caused the upper lugs to eat each other. Take the barrel out of the slide and look at the leading edges of the lugs in the slide. If they are rounded or chipped then the gun is a lost cause. I have also seen others eat barrel links like candy because the barrel wasn't fit to the slide & frame properly.

 

I would suggest sending it back to STI to fix their crappy initial build. A properly fit barrel should NEVER break the barrel link. There were a bunch of the STI DVC Series guns which looked like they were built by monkeys. Yours is likely one of them.

[jimbullet]

22 minutes ago, CHA-LEE said:

I hate to say it buddy but the STI DVC Series of guns usually had HORRID barrel fits. I have seen a bunch of them where the slide lock pin hole in the barrel link was hogged out to a preposterous size which caused the upper lugs to eat each other. Take the barrel out of the slide and look at the leading edges of the lugs in the slide. If they are rounded or chipped then the gun is a lost cause. I have also seen others eat barrel links like candy because the barrel wasn't fit to the slide & frame properly.

 

I would suggest sending it back to STI to fix their crappy initial build. A properly fit barrel should NEVER break the barrel link. There were a bunch of the STI DVC Series guns which looked like they were built by monkeys. Yours is likely one of them.

you mean the slide stop diameter used is too big? Would then a smaller size diameter fix that? The edges of the upper lugs in the slide I can see is actually shinier than the middle/ center lugs, almost like silvery glass finish. It's not chipped but Im not sure how to tell if they are rounded. But I can't see any scuff marks on the barrel lugs at all.

[CHA-LEE]

24 minutes ago, jimbullet said:

you mean the slide stop diameter used is too big? Would then a smaller size diameter fix that? The edges of the upper lugs in the slide I can see is actually shinier than the middle/ center lugs, almost like silvery glass finish. It's not chipped but Im not sure how to tell if they are rounded. But I can't see any scuff marks on the barrel lugs at all.

You are correct, a smaller diameter slide lock pin hole in the link would help fix the upper lug issue, but then could lead to the Barrel bottoming out on the link instead of the frame and breaking. Hogging out the slide lock pin hole in the link is a bandaid to fix barrel that was fit poorly in the first place.

 

When a barrel is fit and timed properly the ONLY job of the barrel link is to pull the barrel down out of upper lug engagement as the lower lugs clear the slide lock pin. After that initial downward "Tug" the barrel links job is supposed to be complete.

 

The problem with the 1911 design is that a barrel can be fit incorrectly causing the barrel to bottom out on the link instead of the frame when the barrel is in the Down & Back position and this will "Work" until the barrel link eventually breaks.

 

If your gun was built properly using a #3.5 barrel link, then you should be able to simply put a new #3.5 link in there and it should pass all of the timing tests and work fine without breaking the link again. I don't want to say that barrel links are always made perfectly and they never break due to manufacturing defects. Anything man made can and will have the possibility of failing prematurely. But the Probability of a barrel link being made incorrectly to the point of it failing is very very low. Versus the HIGH probability of someone fitting the barrel incorrectly. This is especially true on the proven horrid build quality track record of the STI DVC 2011's.