My Commander is locking open

[PinnedAndRecessed]

I have a new Combat Commander with steel frame. It's a series 80. The only aftermarket mod is an ambi safety. It's had maybe 150 rounds through it.

I took it to the range today. Out of 50 shots it locked open, prematurely, about 10 times.

When I say it locked open prematurely, I mean the slide lock lever engaged before the clip was empty. The slide was locked open. The magazine dropped out with no problem.

I shoot left-handed. I also wear shooting gloves. I thought at first that I was somehow inadvertently pushing the stop up.

But then I was very careful to shoot without touching the slide stop. And it still happened.

Any suggestions?

 

[pcf]

The nose of the bullets in the magazine are probably contacting the slide stop. Remove the slide, reinstall the slide stop, insert a loaded magazine and check to see if a bullet is contacting the slide stop. If it is you can contour the slide stop with a jeweler's file.

The other obvious possibilty is that there is no detent drilled in the slide stop or it has been drilled incorrectly. There should be a small detent at the rear of the slide stop so that the plunger can hold it in the down position. If the detent is not there one can be added easily.

If it has been drilled incorrectly you might be able to drill a new one if it's not too deep.

 

[wally]

Most makers are leaving off the dimple on the slide lock lever so the plunger has little to work with. I think the new PTFE "super lubes" add to the problem.

As a lefty, are you sure the slide locked open in the full back positon? I say this because the cross-pin on the slide lock lever seems to be made longer on most makes these days to help with takedown, but this extension makes it very easy to put side pressure on the pin which will often cause the lever to slip into the take-down half moon cutout. If this is the issue change your off-hand grip or grind down the cross-pin so its nearly flush with the frame.

If this is not the case, the next thing to do is check if the rounds are hitting the slide lock on the way up to feed from the mags. Sometimes its a defective mag that lets this happen, but usually its the lever protrudes too far inside.

A different brand of ammo might also be the solution, but I prefer to fix my guns so they'll work with any SAMMI spec ammo.

To check, remove the slide and insert the lever into the frame without the barrel or slide installed, make sure the lever is in the full down position. Then insert a loaded mag and strip the rounds from it one by one. As the rounds move up you should be able to see if they contact the lever on the way up. If they do it should be obvious if its because the mag is cock-eyed (defective) or the catch protrudes too far into the frame. If the later, replacement with in-spec slide lock lever is the solution. Its generally not hard to do a little touch up file work on your lever to cure the issue if you don't want to send the gun back. Just be careful you don't cut it too short to catch the follower.

If none of the above, you could try a stronger plunger spring or cut the dimple (or file a line) to give the plunger a little more to work with. Be careful to not make it too deep or you can prevent the slide from locking back.

HTH,
--wally.