1911 w/ premature slide lock

[Ak Guy]

What (besides my left thumb) could cause slide-lock in mid-magazine? I've had it happen several times, and even when I'm purposely holding my left thumb WAY high, or WAY low, or WAY away from the lever. I'm 99.9% sure it isn't my thumb hitting the lever in recoil, but.........what else could it POSSIBLY be ?? (My right thumb rides the thumb safety, so that's not it) ........thanx......

 

[BigBore44]

How freely does the slide lock pin move? If it's loose, it "could" be bouncing up during the cycle.

 

[FL-NC]

That thing is supposed to be activated by your thumb or the follower on an empty mag. If your thumb isn't hitting it, I would say there's something weird going on with the mag (you didn't say if it happens with multiple mags) or there is something out of spec with the slide lock.

 

[Jim Watson]

Might be recoil. How is your plunger and spring?

Might be the nose of the bullet coming up in the magazine. Look for copper tracks on the slide stop lug. Put a loaded magazine in the receiver with the slide removed but the slide stop in its hole. See if there is a chance for contact.
I have filed back a couple of slide stops that the bullet was touching. Filed one too far and had to replace it so go slow.

 

[Panzerschwein]

Oft times preemie slide locks on an M1911A1 are caused by the bullet riding through the mag and up into the receiver, rubbing the inside section of the slide stop. You should CAREFULLY(!!!!) file it away until it doesn't happen. Don't file too much!!!! The slide won't lock back.

 

[Ak Guy]

Thanx Jim W. and Cooldill .....I think you nailed it spot on ! The side of the bullets coming up are definitely rubbing against the inside of the slide stop lug. So much so, that they've worn the bluing off that area ! (Which just tells me EXACTLY where to file !!)
Thanx again.......... (Man, I love THR)

 

[JONWILL]

Thanx Jim W. and Cooldill .....I think you nailed it spot on ! The side of the bullets coming up are definitely rubbing against the inside of the slide stop lug. So much so, that they've worn the bluing off that area ! (Which just tells me EXACTLY where to file !!)
Thanx again.......... (Man, I love THR)

Another reason l like this forum. Lots of good advice and experience from other shooters. I have had this problem in the past and know how to fix it if I ever run into it again