One of those odd, intermittent things that has now happened enough to make me think something might be outta whack, but doesn't happen consistently enough to troubleshoot.
The pistol is an Auto Ordnance 'Thompson Custom' - a SS 1911, and has been (at around 4000 rds) on of the most reliable 1911s I have owed.
When I first got it, it wouldn't lock the slide with some mags, and a closer examination showed that a fair bit of material had been removed from the inner portion of the slide stop.
It also on two occasions, jumped the slide stop out, mid cycle, jamming the slide.
I contacted Auto Ordnance, and they promptly sent me a new stop, gratis, and I installed and put about 1500 rds through it trouble free- until yesterday.
Yesterday at the range, the slide stop ejected right out of the frame, mid magazine. I put it back in, and it ran fine for another fifty rounds. I was running some Federal Hyda shock that felt a bit more snappy than my usual Winchester Ranger, but wasn't P+.
The slide stop looks fine. anyone have any idea what could cause this?
Enlarge the detent where the plunger rests on the stop? The stop is/should be retained by the slide except for at the take down detent in the slide. Perhaps the top of your slide stop is worn or there is enough up and down play with slide to frame to let it sneak out. I had a similar problem with my SR70 Colt. Wilson mags, particularly 10rd ones, would kick the slide stop out of the take down detent on the next to last round. Just the way the follower hit the release. lock the pistol up bigger than hell too since the slide release would be stuck under the slide but not at the detent to go back in.
The only issue I have had mith my Thompson is the front sight (replaced with Millet front and rear sights by the dealer, at no cost to me) came off after firing 20 rounds.
The slide stop should not be ejecting from the gun, at all. I would replace the detent and spring. Are you having any problem with the safety?
There's no detent there now, but I really can't recall one on any of my other 1911s. I thought I'd ask before I filed a groove where I might not need one.
It doesn't *look* worn - in fact, it looks a bit 'frosted' - totally unworn... And there are no issues with the thumb safety - it engages positivly and disengages cleanly, and stays where it's put.
My old nemesis... Thompson... is up to his old tricks, I see.
Assemble the gun and place the slide in battery. Press down on the stop in the same manner as you would to release the slide, and push firmly on the pin as though you were field-stripping the gun and see if it will slip past the slide rail without being aligned with the takedown notch.
If it will... even if it takes some effort... order a decent slidestop.
I like Ed Brown hardcore. They're castings, but they're good castings.
I've got one in a beater and I can't seem to break it, no matter how I try.
I tried pushing it out as you described, not just in battery, but all along it's travel- but it just wouldn't budge, except at the takedown notch- which doesn't look over-sized, but I don't have another 1911 to compare it to. It is also very cleanly cut though the slide- not a trace of slop or any sort of taper, and the cut through the frame looks perfect, too.
edited to add:
The slide to frame fit is pretty tight, and I just now tried to push it out again, this time pulling up on the slide - still neg res.
If you shoot left-handed with the straight thumbs grip, you may be inadvertently pressing on the right end of the crosspin.
If that's not it... I dunno. I've had a couple here over the years that did that particular little trick, and a new slidestop cured it. The real kicker is that the same slidestops in other guns did fine.
The mystery remains unsolved...
Thanks- while I occasionally swtich hands for practice, I mostly shoot righty.
I feel alot better about things if it stumped you.
Since, so far, it's been once about every thousand rounds, I am going to live with it for a bit.
There's one other possibility... slight though it may be.
Check the slidestop lug for jacket material transfer. If it's there, pull the slide back so that the magazine is uncovered to let the next round rise to feeding position... and look to see if the stop lug is aligned with the takedown notch.
Most bullet to lug contact causes premature slidelock, but it's possible that... with just the right contact... it could place a side load on the stop. Done at exactly the right time, it could walk it out far enough to tie up the gun.
I remembered seeing that happen once, many years ago on an early Springfield. Stoning the tip of the slidestop lug took care of it. I haven't seen that happen since then.
None of your weapons has detents in slide stop? I have a special drill bit which goes through plunger tube and puts detent spot so it can be deepened by Dremel or Dumore. It will definitely stop the slide stop.