1911 falls to half cock on mag change - help?

[dansedgli]

I havent used this gun for a few months.

When I dug it out I shot a stage and the hammer dropped to half cock when I changed mags.

I put more tension on the left side of the sear spring but it did it again tonight.

I had a good look and it looks like the rounds in the mag are hitting the front corner of the disconnector.

It seems people file this area to stop the mag hitting when fitting but I'm curious as to why this has started happening now as it hasn't been a problem for approximately 20k rounds.

Any ideas?

Thanks,
Dan

[Powder Finger]

back top of the top round in mag hitting disconnector. I think there's a pic here somewhere of where to remove metal on the disco.

basically the front edge or mag well side of the square hole.

[Nghthwk1911]

How about after 20K rounds the sear is wore out.... just saying.

[repins1911]

If you have the parts laying around, try changing the ignition system out starting with the disco, and then just process of elimination. Nighthawk has a good point, parts do wear out, take a good look at your hammer and sear engagement surfaces. Good luck and let us know what you find.

[zzt]

My bet is the hammer hooks need recutting. The problem is that when you remove enough material to get a flat sharp surface with the hooks at .020" or more, you change the geometry and have to recut the sear to match. If you have access to a True Radius sear jig, that's easy. If not, you'll have to cut the sear angle to exactly match.

If the sear is damaged and you have to replace it, you may also have to fit a new safety, or get the old one welded up and recut. Since you got 20k out the parts before you encountered this problem, they had to be good parts and fit properly to start with. It is very likely that 15 minutes with a stone and a jig will cure the problem for another 10k or so.