Last time I had it out, I found the firing pin stuck forward. I rebuilt this pistol with new springs and pins. I have about 750 rounds through it and no trouble till now. I worked the firing-pin hole with a needle file, polished up the pin and fired 100 rounds with no more sticking. What could have caused that problem?
The only thing I could think of is a worn pin that is getting canted in the firing-pin tunnel and displacing metal, eventually causing a bind?
Should I leave well enough alone or just go ahead and replace that pin?
Likely peening around the firing pin hole from the base of the cartridge case slamming into it under recoil. If the Argentine slide predates the modification that entailed the hardened steel insert in the breechface... or before they began fully hardening the slides... that could be your bug.
Even hardened slides will exhibit this deformation if they're shot long and hard enough. I have it in an early Colt 1991A1 slide that also cracked in the port adjacent to the breechface from the same stresses. Estimated round count was 150,000-ish. It never caused the pin to stick... but if it hadn't cracked, it probably would have in a fairly short time.
The breech face on this pistol looks kind of ugly. It's indented and looks pretty battered.
Quote:
The breech face on this pistol looks kind of ugly. It's indented and looks
pretty battered.
Bingo. Either a hard-used pistol or a soft slide. You'll see a lot of it in the old USGI and commercial Colts built prior to 1936, when they started the insert mod.
Might wanna check the rear faces of the slide lugs for deformation. They'll look like a stair step. Get it clean and look at'em under a good light.
Thanks, Tuner, I'll take a good look at it when I get home, I'm away right now.
Any safety issues with that breech face? Could head-space become an issue?
Probably not from the breechface alone, assuming that it was mid-spec when it was new, and assuming that the barrel is still original to the gun. Other things could assuredly affect it... like the deformed slide lugs that I mentioned.
I'll will give it a good look when I get back but I do now remember those lugs looked perfect on both the slide and barrel. No peening at all.
Don't laugh, but when you detail stripped your pisto, you didn't accidentally put the firing pin spring backwards did you? One end of that spring is smaller that the other and might cause the problem you described.
Or a cracked/broken firing pin spring...