MKIII 22/45 I'm Baffled. Any Suggestions?

My MKIII 22/45 trigger consistently fails to reset on the last round. It feeds the round into the chamber but the trigger does not reset. This happens about 90% of the time.

It occurs with all 4 of my magazines. (Which are clean and in good condition.) Does anyone have any ideas or suggestions? :?:

Also, I removed the mag safety replacing it with a BAM bushing and replaced the trigger and sear with a Volquarten target sear and target trigger. The gun has only 3500 rounds through it. It drives me crazy when shooting timed and rapid fire.

If it functioned fine before you changed parts, change it back and see what happens.

Sorry ..... that's all I got.

You may need to back off of the pretravel setting screw on the trigger a few turns so the trigger can return fully forward.

That's all I got...

If it only happens on the last round, the follower is touching something that a round in the magazine is not. Pull the top, and insert a loaded magazine, then an empty magazine, and see where the follower is touching that a round is not. If you can't see any difference, then when the pistol is assembled, the follower may be pushed to one side by the bottom of the bolt and then contacts the disconnect.

Actually, and not to be "nit-picky", the follower has nothing to do with engaging the bolt face to hold the bolt backward, or impede rounds from feeding. The OP even mentioned that the last round will feed but it will not fire due to the hammer not going forward.

When you mean "reset", I assume you're referencing the sear to hammer re-engagement? I would then try backing off the pre-travel screw in the front end of the VC trigger. But, you only need to go a "quarter-turn" at a time until the sear/hammer begins to reset once again.

When you installed the VC parts, did you clean the screw threads and threads in the trigger with acetone, or a spray parts cleaner and then apply a drop, or two, of thread locker? If there's any packing/assembly oil left in the root of those thread those two screws are able to move out of adjustment quite easily during the firing sequence.

Nope... I never said the follower is impeding the bolt.

Here's the deal - it only happens on the last round - that's a clue. When the last round is fired, the pistol cycles, and in so doing, strips the last round from the magazine and returns to battery - this happens before the trigger is released. Now, the bolt is in position, and possibly, the follower is riding against the bottom of the bolt if it is tall enough. The follower may move side-to-side a bit and may contact the disconnector, preventing the trigger from resetting. A round in the magazine is held firmly in place, and will stay centered.

Again, with the top removed, try a loaded magazine and an empty magazine and look for any differences. Maybe try wiggling the follower to the right and see if it contacts the disconnector. Hard to believe that the follower or the magazine could move that much, but the take-up adjustment is fine for all but the last round. The only thing that has changed is that the follower is at the top of the magazine rather than another round.

And like the OP posted in Post #1, "it happens with all 4 of his magazines" ? I rather doubt that ALL of the followers themselves are being impeded, at least during the 46 years that I've been working on these pistols, I've never seen how the follower could be causing what he's experiencing.
Now, as my second recommendation, the follower "thumb button" which is what could be being impeded by the bolt stop assembly, in all 4 magazines, may be what's preventing the follower itself from going all the way upward, which is possible, as the bolt stop assembly is activated by that thumb button. Awfully difficult to diagnose an issue from afar, and not on my bench.
I assumed that the OP was looking for a specific place to look for the issue, rather than a vague "something is preventing". It's quite obvious that "something" is causing the issue, right?

This sentence you posted is extremely confusing: "the follower may be pushed to one side by the bottom of the bolt and then contacts the disconnect."
I don't see how that could possibly happen, the follower is contained by the magazine feed lips, so how could it ever hit the disconnector?

SGW Gunsmith said:

. . . . . When you mean "reset", I assume you're referencing the sear to hammer re-engagement? I would then try backing off the pre-travel screw in the front end of the VC trigger. But, you only need to go a "quarter-turn" at a time until the sear/hammer begins to reset once again.

When you installed the VC parts, did you clean the screw threads and threads in the trigger with acetone, or a spray parts cleaner and then apply a drop, or two, of thread locker? If there's any packing/assembly oil left in the root of those thread those two screws are able to move out of adjustment quite easily during the firing sequence.

Click to expand...

A hearty thank you to all who have replied. I appreciate all your suggestions and comments.

SGW, yes, by "reset" I am referring to the sear to hammer re-engagement. I will try backing out the pre-travel screw a quarter turn and see if that resolves the problem. That could very well be the problem since there is virtually no trigger "take up" (Also, pull weight is down to 2 lb. 4 oz.) I probably should have thought of that but sometimes it takes another person to point out the obvious. :mrgreen: I'll post results after my weekly range trip on Monday, Dec. 3.

Great thanks again for everyone's replies.

I promised to post results of SGW Gunsmith suggestion: Voila! I backed out the pre-travel screw 1/4 turn and ran through 8 magazines (2 x 4 different mags) and it functioned perfectly. Not a single failure to feed the last round.

As stated above sometimes one can overlook what should be obvious. But, what confused me was that it was only the last round that would consistantly fail to feed. I'm still not sure why but, it's fixed, and I wanted to bring "closure" to this thread. Thanks to all who responded and particularly, SGW GS.