Colt GM locks back, magazine moved up/down freely


Oleg Volk
April 12, 2003, 07:14 PM
My Colt GM started locking the slide back on its own. First once per box of ammo, then one per mag, no once every shot. Coincidentally, I noticed that sometimes magazines won't click into place with the slide locked, and when I manage to insert them, they have about 1/3-1/4" free play up/down.

Next week, I will send that gun to gunsmith Shannon in Knoxville but, in the meantime, does anyone have any guesses as to what's the problem and how to fix it?

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April 12, 2003, 08:49 PM
Your slide lock problem sounds like it might actually be a grip problem; in order for the slide to be mechanically held open, a tab on the magazine follower has to press up on the latch from inside the pistol; if there's a full magazine in the pistol, this can't happen, so something has to be affecting it from the outside (likely, your grip during recoil). A little play in the magazine is normal when it's locked in the pistol, but 1/3 of an inch? Are the mag catch notches in your magazines worn, or are the edges still sharp?

Oleg Volk
April 12, 2003, 09:18 PM
This happens with a variety of magazines, all types of ammo. I've fired this gun before and have never limpwristed it or hit the slide lock by accident. Firing it one-handed yields the same results. Rarely did I get two rounds in a row today, mostly it was slide lock after every shot.

The play in magazines was that great! I am thoroughly disgusted by Colts at this point -- every one I've had developed serious problems.

Jim K
April 12, 2003, 10:15 PM
Hi, Oleg,

I can't imagine any magazine that moves up and down that much. The front tip of the floor plate should keep it from moving up, and the magazine catch should keep it from moving down. This is a fixed relationship and while there are tolerances, the magazine should have very little up and down play.

If it happens with different magazines, it has to be the gun somehow. If the magazine can move up that far, the body of the magazine would engage the slide stop, not the magazine follower.

Please let us know what you or your gunsmith find out. This one has me totally stumped.


April 12, 2003, 10:21 PM
Oleg: Sounds like the slide release is being bumped into engagement by the nose of the bullet during the feed cycle. You could simply change out the slide release with an aftermarket part, or you could try smoothing the area of the slide release that is making contact with the lip of the magazine. Be careful though, if you take off too much from the slide lock tab, the magazines will no longer lock back on empty.

Old Fuff
April 12, 2003, 10:58 PM

Field strip the pistol. Then put the slide stop back. Insert a loaded magazine and be sure it’s latched. Push out the cartridges with your thumb while watching the slide stop to see if the bullet nose or cartridge pushes the slide stop up. After you push out the last cartridge see if the tab on the follower pushes the slide stop up (as it should). Since you can see what is happening you may be able to define the problem.

April 13, 2003, 12:02 AM
I wonder, since this problem recently cropped up and gets worse I wonder if his magazine catch could somehow have become broken or worn from use. I have heard of them breaking before. This would explain the magazine movement. Or if you are using Colt mags try others, I have one Colt mag that moves up iand down alot more than any other I have.

Also check to see if there is still tention on your plunger spring, if there isn't anything holding the slide stop in place it could be bouncing up freely with recoil.

I might be wrong but just a few ideas.

Oleg Volk
April 13, 2003, 05:13 PM
Plunger has tension, magazines should be OK. I think something is wrong with the magazine release but lack expertise to fix it myself. Maybe Tam could ferry the pistol to her gunsmith when she comes to visit...I meant to have the gun looked at anyway.

Johnny Guest
April 17, 2003, 03:28 PM
What kind of ammo are you using. Certain bullets, if seated too far out or if they are very broad nosed, can actuate the slide stop, especially if the SS if just a touch over long.

You say GM--A Colt-brand Government Model, correct? Commercial production, or GI? If commercial, which one--Pre-1970, 70-series, or Series 80?

Magazine movement of as much as one-quarter inch is a LOT. Has the magazine catch been modified? Do you or a close friend have another pistol so you can try swapping some parts out? If this up-and-down play is with different mags, I would suspect a too-small mag catch area.


April 17, 2003, 03:42 PM
It sounds like you have a problem with the mag release.

Oleg Volk
April 18, 2003, 12:51 AM

Wanna come by on the 26th (my birthday party) and take a look at it? The Colt is a 1957 commercial gun, and problems happes with a variety of mags. It was 100% reliable before.

El Tejon
April 18, 2003, 03:18 PM
Did you try lubing the mag release??? 1911s are mudders. They love the oil.:D

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