Can anyone tell me what the troubleshoot is if my gun's slide is not locking back after the magazine empties? My gun is near brand new and its getting very aggravating. Its a new Gold Cup Trophy and I have only been using the 7 and 8 round mags that came with it, both result in the same failure.

Love the gun, annoyed with this...

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German Shepherd, Colt GCT, and a Darn Nice Beard... All I need now is a Flux Capacitor and Im complete.

Sounds magazine related to me. Have you tried bumping the mag with the palm of your hand to seat it properly if needed? By chance, have you changed out the stocks/grip panels on your GCT?

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Does the slide lock back when you manually pull the slide back?
If it does not stay back then, the follower is not engaging the slide release.
It may be an out of spec slide release, too short. The mag followers could also be a problem, but both mags having a follower problem is unlikely.

If the slide does not stay back during firing only with both mags, then the mag springs are too weak, even if they are new. Get some Wolff springs that are 5% or 10% more than factory rating.

I have not changed a thing on the gun, and yes I can lock the slide back manually it is only when firing the gun that i have the issue. I will try the springs and see what happens.

Thanks for the help!

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"It's not who I am underneath, but what I do that defines me."


German Shepherd, Colt GCT, and a Darn Nice Beard... All I need now is a Flux Capacitor and Im complete.

Possibilities:

1. Slide stop out of spec (not likely since it works manually, but still possible)
2. Followers (not likely for the reasons previously stated, but again still possible)
3. Weak mag springs
4. Plunger tube/Plunger/Spring is it working correctly and putting tension on the slide stop?
5. Shooter induced - folks with large hands and/or shooting with a thumbs forward grip sometimes end up riding the slide stop

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+1 on garrettwc's diagnosis. These are the only reasons that the slide will not lock back. As a firearms instructor, having seen it hundereds of times I am betting on #5. This happens to me when using the thumbs forward on a Glock. Configuration is different and doesn't happen to me with my Gov't Model.

LHS

It's the slide stop my Colt Gold Cup I Bought in 1993 did the same thing and it was new.
Sent it back to Colt that was what was wrong with it they fixed it never had a problem since.

Hmm, well I am going to try to figure it out, I'd like to avoid sending it out, Im just a little paranoid about that...

They told me where I bought it that mag springs would more than likely fix the problem, actually they recommended wilson combat mags to replace the mags that came with the gun and to see if colt would replace the springs that came with the gun. Such an annoying problem to have.

As for number 5, i don't have my thumb near anything, my palm is large but my fingers are a bit thin so there is plenty of room above my thumb, besides i keep it bent downward slightly, if that makes sense...

It will lock once every once in a while. I'm trying to get one of my friends to lend me one of their magazines to test the theory... we shall see, but i hope thats it.

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"It's not who I am underneath, but what I do that defines me."


German Shepherd, Colt GCT, and a Darn Nice Beard... All I need now is a Flux Capacitor and Im complete.

Had the issue with a NIB Gunsite CCO purchased within the last year. The slide wouldn't lock back with one of the two mags provided with the pistol. I bought a quantity of new Colt mags, and exactly half of those yielded the same result. Colt happily exchanged mags, but the yield was still the same--half of the mags wouldn't cause the slide to lock back.

I got tired of swapping mags with Colt and had success with adjusting the lip on the follower that engages the slide stop. The adjustments were extremely small and were performed with a high-tech pair of pliers. Adjust--try a couple of rounds--adjust again--repeat as necessary. Finally got half a dozen mags that worked 100%.

Then, to protect the aluminum rame of the CCO, I bought Tripp mag overhalul kits which include a spring and the hybrid follower. All of the mags worked 100% after the Tripp mod with no further adjustments or tinkering and haven't had any problems since. So, I fixed the problem twice, the first time by adjusting the factory mag followers, and the second time by installing the Tripp mod kits. Whether this has any relevance to the thread issue....??? but that was my experience.

Some years ago I had a brand new Colt 1991 Officers ACP with the same malady. A Wilson slide stop cured it.

There's a wealth of information in the Gunsmithing stickies on this and other matters. Worth looking up. The dogs need to go out or I'd include the link .

Regards,

Walt

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Author, The M1911 Complete Assembly Guide,
The M1911 Complete Owner's Guide,
The M14 and M1 Garand Complete Assembly Guides
and The AR-15 Complete Assembly and Owner's Guides