I just finished one, and I'm working through some bugs. No big deal, but here's a strange one:
I have an intermittent problem. Normally the hammer, trigger, sear, and disconnector operate fine. Once in a while (maybe every 25 shots), when I pull the trigger, the hammer stops before hitting the firing pin. (get caught on the safety notch as when you pull the hammer halfway).
It is happening less than when it was first built, so it may be going away... but I'd like to figure out what is causing it.
Before I get into checking everything out, I thought I'd ask and see if anybody has had this problem before?
Back out your trigger stop. until the sear no longer "rubs" on the half cock. Best notch the center top of the sear, narrow the half cock by 1/3d off of each side, like the Gold Cup. then half cock and full cock engage different areas on the sear,and you can bevel the back of the notch and the front corner of the half cock. That lets you run in the trigger stop screw about another half turn.
I did a light trigger job on my Colt Commander, approx 1.5 lbs, got the trigger stop screw a fraction too tight and found that when dry firing or when I first started shooting it was okay. Once the metal heated up enough from an extended firing session started having the same problem you're experiencing. Tolerances were tight enough that when the metal was cold it wasn't a problem but when it heated up, the metal expanded enough to cause a problem. Backed off the stop screw about 1/4 turn and got rid of problem.
Basically, your trigger is not pushing the tip of the sear far enough forward to clear the half cock notch. I'm not sure I'd go to the trouble of all the mods wasntme referred to. Trigger pull was fine without all that and it's still working great now, about 10 years later.
Before wasntme or anyone else flames me about such a light trigger pull, this is my range gun, my project piece to test modifications, not my defense piece.
It was "rubbing" half cock when cold, too, you just never noticed until it actually CAUGHT.
I don't use an adjustable trigger and I'm not really sure what a trigger stop screw is. (I only use them for defense, so I just want to have 100% reliability.)
So the problem is the trigger isn't travelling far enough rearward? How could I take care of this on a standard (non adjustable) pistol? Is it possible the tip of the sear needs to be filed?
More likely, the trigger is just too short, or the frame is out of spec. The latter is pretty much de rigueur for Tannery 80% frames, in my experience, (and that of many, many other builders as well). I'd not cut on the front of the sear, except as a very, very last resort, or only on a cheapo, surplus sear, as an experiment, then repeat with a quality sear. The pin holes in 80% frames are notoriously mis-located, and not at right angles thru the frame. So, often one has to get "creative" to get a decent trigger pull on one.
Thanks for the info... but I'm still not getting it. What is it that's out of spec? If I know what it is that might be out of spec with the trigger/trigger guide in the frame, I can modify the frame to accomodate.
What exactly do you think is happening that's causing the sear to engage when the hammer is halfway down?
sorry, thought you would understand the overtravel screw reference. those engage the magcatch,limiting rearward travel of the trigger. somethingis not letting your trigger move back far enough, so that it will rotate the sear enough, to clear the half cock notch as the hammer rotates forward. Best thing would be to use a caliper, and compare your frame and trigger to a known-good frame and trigger. Does it happen both with and without a mag in place?
I see what you're saying now... it has only happened without a mag in place. But now that I think about it, the mag catch that I'm using is a pretty hokey one... Maybe that's the source of the problem.