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Old February 2, 2021, 10:42 PM   #1
CedarGrove357
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Virgin 1911 cycling issue

I searched the forums, and found nothing related to my issue, perhaps some of the more seasoned smiths may help out. As part of my schooling, my instructor is encouraging me to resource resolutions for this issue.

I am building a 1911 from scratch for school. All our parts were sourced by the school and require smith level fitting to function. I built the firearm and have successfully shot it, and its passed all of the safety tests. However, it has one really annoying problem and I cannot seem to resolve it on my own.

When the frame is held in the left hand, right hand on top of the slide with the thumb on the serrations, effectively putting pressure to the left behind the ejection port, the slide cycles fine. If I switch hands, the slide will stop about 1/8" back. Here's the annoying part, if I torque the slide with my hand to replicate the pressure from my right hand, the slide will cycle.

My hypothesis is focused on the feet of the barrel. I've been able to reproduce the issue with only the slide lock, disconnector and barrel installed. When I blacken the feet and create the issue to see where the slide stop is landing on the feet, the only marks are at the back of the feet behind the barrel lug as they should be. The marks also appear even, and no other marks are evident through the travel of the barrel lug.

What could I be missing?
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Old February 3, 2021, 12:19 AM   #2
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I'll take a stab at it, but I'm not a gunsmith, don't pretend to be one. What I do have is a half century of familiarity with the Colt Govt Model, M1911 and M1911A1 as well as some "1911A1 pattern" pistols. Did a hitch in the Army in the mid 70s as MOS 45B20 Small Arms Repairman.

First off, this...
Quote:
All our parts were sourced by the school and require smith level fitting to function.
GI 1911A1s do not require smith level fitting. Proper milspec parts do not and should not require ANY fitting. So, you're not working with those, by intent, you're building a "fitted" gun. Not a GI milspec 1911A1.

ok, now first question, you've fired the gun...one round?, one full magazine?? and it functioned, how? normally?? or did it hang up in any way??

Next question, when you say the slide "cycles fine" you mean empty (unloaded) cycled by hand?? with or without the recoil spring in place??

When you say the slide stops about 1/8" back, ..back from what? do you mean it stops 1/8" back on opening? or 1/8" from fully closing??

Quote:
When I blacken the feet and create the issue to see where the slide stop is landing on the feet, the only marks are at the back of the feet behind the barrel lug as they should be.
this part confuses me. Clearly we are not understanding terms the same way. To me, the barrel lug(s) are on the top where they lock into the slide. The "feet" are the lower portion of where the link is installed (if you want ot call that a lug, we can do that) but the slide stop "pin" portion only contacts the front of the "feet" at full lock up. Not the back.

So, we need to get on the same page with our understanding of terms, otherwise all we're going to be is confused.

I'd like to help, but I need to understand what you mean.
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Old February 3, 2021, 01:01 AM   #3
CedarGrove357
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Thank you so much for the time in your response 44AMP. Hopefully I can clarify. Guess I should have opened it up to "any with experience". I also didn't want the post to be too long.

Yes, we are building a "fitted" 1911 from a stripped slide and frame. We've had to fit the trigger, thumb safety, grip safety, barrel, slide stop, barrel bushing, barrel lug, extractor and the slide to frame fit. As a gunsmith school, they are carrying us through possible scenarios we would encounter when having to fit new parts into firearms. We had to then go through safety checks and test fire. I fired a single round to test, which didn't clear the extractor, but didn't stove pipe. Testing the extractor indicated it was too tight, so I adjusted and fired 3 more rounds, first stove piped, subsequent two ejected ok. slide cycled completely, and held open on last round.

In testing, completely assembled, the slide will work holding the frame in my left hand as described. When I switch hands, the slide will only move back about 1/8 of an inch before it stops. If I adjust or twist the torque from my hand that is on the slide, I can then get the slide to cycle completely back without an issue. This is repeatable.

In troubleshooting, I started removing components to attempt to isolate the offending part. I removed all components associated with the slide, hammer, mainspring housing, grip safety, thumb safety, hand spring. With only the barrel, barrel bushing and slide stop installed, I can cycle the slide and again reproduce the issue.

The part about the barrel feet was a typo. the "barrel lug" should have been the barrel link, not lug. apologies. concerning the feet, we had to fit the link to the barrel feet manually by filing the feet to fit. I measured the barrel to determine the proper link I needed to use from the kit. To check for issues of contact in the travel of the link with the slide stop pin, I would use a black sharpie to "blacken" or color the feet, assemble the slide stop through the link and activate the motion of the link to see where the pin would rub on the feet and file for clearance. After doing this a couple of time, I found the stop pin was rubbing on the feet and cleared that, but the issue remains. I do not want to continue to file on the feet, removing material ignorantly if something else could be causing the issue as well.

Hopefully this clarifies the fog a little. Thanks again so much!!
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Old February 3, 2021, 01:20 AM   #4
CedarGrove357
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Here's a pic of the gun . . .

20201201_130529_1024.png

20210126_152416_1024.png
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Old February 3, 2021, 01:52 AM   #5
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1/8 of an inch back is just about where the barrel should be starting to unlock from the slide. My first guess is that the fitting of the barrel to slide is slightly off and the barrel (top) lugs are hanging up on the slide lugs.

Slather the barrel lugs up with light grease or heavy oil and see it the problem goes away, or becomes less severe.

You may also have too long a barrel link installed. Have you run Scheumann's barrel timing test?

https://www.m1911.org/testkit.htm
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Old February 3, 2021, 01:56 AM   #6
CedarGrove357
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Quote:
Originally Posted by Aguila Blanca View Post
1/8 of an inch back is just about where the barrel should be starting to unlock from the slide. My first guess is that the fitting of the barrel to slide is slightly off and the barrel (top) lugs are hanging up on the slide lugs.

Slather the barrel lugs up with light grease or heavy oil and see it the problem goes away, or becomes less severe.
Will do that first thing tomorrow. This has put me a little behind as the next phase is finishing - bluing, cerakote, parkerizing.

Thanks 10^10 Aguila! I'll post the findings.

Other input still welcome!!
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Old February 3, 2021, 01:56 PM   #7
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Quote:
When I switch hands, the slide will only move back about 1/8 of an inch before it stops. If I adjust or twist the torque from my hand that is on the slide, I can then get the slide to cycle completely back without an issue. This is repeatable.
OK, thanks for clearing up some of my confusion. Now, again, to be clear, the slide stops 1/8" back when you are cycling it by hand, (and with no recoil spring in place??)

Is it a "hard stop" jamming things? Is it something you can "pull through without putting the sideways pressure on the slide?

You said you fired a couple rounds and it worked properly, so what ever is binding isn't binding enough that the force of a fired round couldn't "power through it".

I'm under the impression that this problem is something you are only finding when working the slide by hand with the pistol partially stripped. And not a problem you are getting with the fully assembled pistol. Is this correct??
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Old February 5, 2021, 12:30 AM   #8
CedarGrove357
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Quote:
Originally Posted by 44 AMP View Post
OK, thanks for clearing up some of my confusion. Now, again, to be clear, the slide stops 1/8" back when you are cycling it by hand, (and with no recoil spring in place??)

Is it a "hard stop" jamming things? Is it something you can "pull through without putting the sideways pressure on the slide?

You said you fired a couple rounds and it worked properly, so what ever is binding isn't binding enough that the force of a fired round couldn't "power through it".

I'm under the impression that this problem is something you are only finding when working the slide by hand with the pistol partially stripped. And not a problem you are getting with the fully assembled pistol. Is this correct??
It is a hard stop when the issue happens. I have to release pressure and change torque then I can get around the stop. If there is no pressure left or right, the firearm cycles fine as a complete weapon or when partially broken down.

I took Aguila's link and followed the instructions as best I could. I have a 0.020 shim stock and a 0.015 and 0.005 shims as well and checked the hood clearance when the barrel unlocks the lugs when the slide begins to unlock. The .015 shim fit between the barrel hood and the front lower edge of the ejection port, but .020 would not fit.

I further checked the barrel feet again, and it looked under magnified inspection that one of the feet tips is slightly longer than the other and more pointed. I rounded the foot to match the shorter one and it seemed to help the issue. I also filed a small amount at the back of the frame where the lower legs hit the frame to stop rearward travel. I think I loosened the issue somewhat, but had to abort and start polishing and getting the weapon ready for our next lessons in bluing and cerakoting.

We have 3 weapons we are building to some degree - a 1911 fit, an AR15, and a Weatherby in .308. All of which are in various stages of production.
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Old February 6, 2021, 03:44 AM   #9
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Quote:
My first guess is that the fitting of the barrel to slide is slightly off and the barrel (top) lugs are hanging up on the slide lugs
That would be my call as well. Sounds like your locking lugs are hanging up when opening. Your thought on the barrel feet is kind of in the same direction, the barrel is not coming far enough down at the rear to fully unlock.
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Old February 6, 2021, 09:33 AM   #10
CedarGrove357
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Quote:
Originally Posted by Scorch View Post
That would be my call as well. Sounds like your locking lugs are hanging up when opening. Your thought on the barrel feet is kind of in the same direction, the barrel is not coming far enough down at the rear to fully unlock.
I did suspect the barrel bushing. I probably fit it too tight. I may throw it back in the lathe and scotch brite the inside to see if I can loosen up the barrel to bushing fit to allow more tilt angle at the front. I dismissed it because the busing to barrel fit outside the slide was tight but ok. Sometimes tolerance stacking can get the best of a situation.

I wouldn't be so picky on this issue if it was just my gun, but since I am learning this with the projection of creating them for sale, I am being much more finicky with issues which may come back as a QC issue.

Thanks all for your time and entertainment of this quirk.

Cedar~
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Old February 6, 2021, 01:47 PM   #11
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I agree with AB that it sounds like the locking lugs are not dropping the barrel soon enough. The barrel turning slightly in the slide might make the difference that explains the slide torque effect.

Quote:
Originally Posted by CedarGrove357
...concerning the feet, we had to fit the link to the barrel feet manually by filing the feet to fit.
That's the part that sounds odd to me. The way I was taught was to get the slide, barrel, and bushing fit. The slide/barrel/bushing assembly goes on and off the frame as you file and scrape the link lugs until the barrel, pushed down into the frame with your finger when the slide is in counterbattery, locks it up firmly into the slide by riding the slide stop's assembly pin into position as you move the slide forward. When all that is done, then a link that fits is chosen. Link kits come in 0.002" hole spacing increments for that reason. So I'm not sure how your timing is landing.

It also occurs to me to ask if you used a scraper to break the trailing edges of the slide locking lugs and the leading edges of the barrel locking lugs? A short (0.015"-0.02") 45° chamfer on them improves reliability and makes the exact fit of the link a little less critical. Hallock illustrates this on page 121. He refers to these broken corners as the lug's "camming surfaces".
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Old February 6, 2021, 02:21 PM   #12
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Quote:
Originally Posted by CedarGrove357
...concerning the feet, we had to fit the link to the barrel feet manually by filing the feet to fit.
Were you taught to do it that way??

seems backwards to me. As a general rule, one fits the smaller, cheaper, replaceable part to the larger more expensive one, not the other way around.
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