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  #1  
Old 07-19-2008, 06:38 PM
Huck Colt 1911 Huck Colt 1911 is offline
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Barrel Lock-Up Question




A club member in our NRA Action Shooting Pistol Club is looking for a mid-price 1911 and has been advised by other club members to look for the following in the purchase of a 1911:

1. Tight slide to frame fit,
2. Tight barrel bushing and
3 Tight barrel lock-up.

IMO, barrel lock-up is when the slide is fully forward or in the battery position.

Question: What makes for a tight barrel lock-up and how do you test for it on a new 1911?

Any guidance on this is greatly appreciated. Thanks.

Huck
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  #2  
Old 07-19-2008, 07:00 PM
xring45acp xring45acp is offline
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Barrel Lock-up

Huck Colt 1911, Well I will try to explain barrel lock-up. When the barrel returns home in the lock-up position the upper barrel lugs are engaged with the slide lug recesses. This contact point of the lugs and their corresponding recesses are important as is the amount of contact on each bearing surface. The lower barrel lug must be also resting on the slide release with a equal amount of contact surface across the diameter of the slide release cross-pin as well. The barrel hood just above the chamber must have a very slight amount of tolerance as it mates in the breech face slot aiding in consistant return to battery position and still be reliable. Moving on to the other end of the barrel, the barrel bushing must have minimal clearance as well so that it will not let that end of the barrel shift and vary other shots. Usually I check for barrel tightness by pushing down on the top of the barrel chamber as it is in lock-up position, this will tell me if there is a little play in the barrel link. Sorry for being so winded. There is alot more to this if you are building for precision accuracy, so I will stop here at the basics.

Thanks, xring45acp
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  #3  
Old 07-19-2008, 07:56 PM
Huck Colt 1911 Huck Colt 1911 is offline
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Barrel Lock-Up Question

It certainly appears that you are a knowledgeable pistolsmith. The importance of tight tolerance on the lugs, corresponding recesses, barrel hood and barrel bushing make for an accurate 1911. You also stated that you check for barrel tightness by pushing down on the barrel chamber to test for any play in the barrel link. When purchasing a new 1911, is this the test that shows a tight barrel lock-up? It appears that a gunsmidth would need to test for the tight tolerances to determine if you have the proper barrel lock-up.

Thanks,

Huck
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  #4  
Old 07-19-2008, 08:33 PM
xring45acp xring45acp is offline
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Barrel Lock-up

Huck Colt, The variables in checking for a "Tighter" lock-up are:
BARREL QUALITY!
Frame to Slide clearance for the full length of travel.
Barrel hood clearance - fitment, to breech face.
Total lug fitment top and bottom.
Bushing to Slide fitment.
Bushing to barrel clearance.
Proper Barrel link length.
PROPER LOCK-UP can still be achieved with loose tolerances in the assembly!!!
This is just a checklist for a tight fitment of the upper assembly.
My checklist and other pistolsmiths will vary as the experience level changes as well as opinions, however most all will check at least the above!

Thanks, xring45acp
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  #5  
Old 07-20-2008, 01:48 AM
acoilfld acoilfld is offline
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Sorry to butt in on this but I have a few questions about lock up in battery.
Can barrel lock up be checked with "Prussian blue" to determine the contact points?
Quote:
Usually I check for barrel tightness by pushing down on the top of the barrel chamber as it is in lock-up position, this will tell me if there is a little play in the barrel link.
How much play would be acceptable?

Thanks
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Still Looking for ANY AR-15 parts you have laying around that I can use to complete my build
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  #6  
Old 07-20-2008, 02:01 AM
xring45acp xring45acp is offline
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acoilfld, Not sure about Prussian Blue as a dye marker, but I use Dykem Blue and a Sharpie sometimes. The amount of play is up to the person checking, and I know that does not tell you anything here. I do not want any downward slack or play when pushing straight down on top of the chamber when the pistol is in full lock-up or in full battery position. This is just my own way of checking for this and not the practice of all pistolsmiths I'm sure.
The amount of play would have to be addressed by a prominant pistolsmith.
My personal customs have "0" play. I like them tight, as they will shoot in as the break- in process begins.

Thanks, xring45acp
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  #7  
Old 07-21-2008, 06:21 AM
richpetrone richpetrone is offline
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Barrel lock up

When buying a used Colt 1911, the "ideal" method to determine if the gun is good, is to be allowed to test fire it. If the owner does not agree that he has the time to test fire the gun with you, then beware.....he may be hiding something. I have seen guns with tight bushings, no play in the lock-up, and good slide fit, that still didn't shoot worth a hoot.
The quality of the barrel is important to good accuracy. Even so, I have seen guns with loose tolerances shoot very well at 25 yards.....it all depends on how uniform the gun locks up.

Anytime you purchase a used gun, it is a roll of the dice unless you get to test fire the weapon. I have seen used guns that cycle flawlessly by hand, yet the gun may be "out of time" and not function properly when fired.
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  #8  
Old 07-21-2008, 10:48 PM
Huck Colt 1911 Huck Colt 1911 is offline
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Barrel Lock-Up

Thank you everyone for your comments. I appreciate the guidance and the info. has very helpfu.

Huck
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  #9  
Old 07-22-2008, 12:41 AM
lilricky2 lilricky2 is offline
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Acoilfld, prussion blue transfers from one surface to another. Essentially, it smears from one surface to another. I use it to determine contact on load bearing applications like babbited turbine bearings. You want a bluing that dries into a film coating like Dykem or even a magic marker so it will leave a clean, dry visual of an oversized or high spot.

Rick
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  #10  
Old 07-23-2008, 07:16 AM
Chuck S Chuck S is offline
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Match pistols are usually tight, but tight pistols are seldom match pistols. Don't confuse tight for accurate. Give my 3 minutes with a ball peen hammer and I can many a M1911 as tight as anyone wants. Pistols needing a bushing wrench to disassemble are not per se more accurate than those that don't.

The only way top judge accuracy is to shoot the pistol.

Almost any stock M1911 will benchrest cloverleaf groups. Beyond that accuracy is ammo and shooter. Those 1-1/2" accuracy guarantees are not attainable with much of the ammo on the market so take them with a dose, not merely a grain, of salt.

Quick test is to press down on the barrel when the slide is closed. If there's good lockup the barrel won't move. Other that that shoot the puppy off the bench and don't get involved with the trivia of the last 1/64" accuracy, you won't be able to hold at the range with factory ammo.

The stock Springfield Loaded meets all the criteria in an affordable package. Moving higher on the price scale gets a nicer finish, more fully machined parts, and a bit of ego enhancement -- but for putting bullets in a 9" circle no more functionality.

-- Chuck

Last edited by Chuck S; 07-23-2008 at 07:18 AM.
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  #11  
Old 07-23-2008, 08:39 AM
Magnumite Magnumite is offline
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Another check I do assumes you can't make the barrel move downward when pressing on the hood when in battery. I look at the distance the slide/barrel move backward from lock up without the barrel hood dropping. I prefer to see .090" or better, since dropping sooner can cause vertical stringing of the groups.

That being said, shooting still is the best test. I intentionally two pistols ever so slightly "loose" (I can actually force the slide to move a little up and down at the muzzle when in battery, but the barrel doesn't move when I push down on the hood when in battery). One shoots 2 1/2" at 50 yards and the other goes around 3". The bushings on both just barely need help of a bushing wrench to remove, and one I can use a magazine as described in the military field service manual for the 1911 to turn the bushing.
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  #12  
Old 07-25-2008, 05:06 AM
Huck Colt 1911 Huck Colt 1911 is offline
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Barrel Lock-Up

Thank you all. Great and useful info.

Huck
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