Breech block not closing

[Olle]

Originally Posted by Rick W.

Could it possibly be a ammo dimensional thing? I was talking with some folks about their 9mm's that were shooting factory ammo, two guys had factory 9mm ammo that would chamber in some auto's and other auto's not. Both instances were with a bulk box of factory ammo. Not all the cartridges were so affected, just some from each box.

The ammo should be able to insert fully and release with just a tip of the barreled receiver loose and no toggle etc; ie fall in, fall out without manual assistance.

I am a reloader only, but I gotten into the habit of running all my reloaded ammo thru the loose barreled receiver.

Sounds like you are homing in on it..............

The chamber is fine, a bullet will drop right in just like you describe it. It actually seems to be on the loose side, so I'm going to check the casings later to make sure they're not bulging. There could be something about the casings the pistol doesn't like though, the rim on the UMC has pretty square edges and you can see pronounced scratches where the extractor has been sliding over it. It's very difficult to tell what's going on here. If I understand the function correctly, the extractor will slide over the rim after the bullet is seated in the chamber. The breech blocks stops before that, but that could be because it actually bounces back from the firing pin pressure. You would need a high speed camera to catch that.

In any case, I checked the extractor and there was some gunk under the claw, but I'd still say that the whole assembly was very clean. I polished the extractor a bit just for good measure while I had it out, cleaned and lubed everything etc. I also found that the breech block is pretty tight in the rails, so I polished it a bit. That actually seemed to slick it up quite a bit, but there's still just about zero play side to side.

Next step is to dig deeper in my safe and see if I can find ammo with a taper on the rim. I would imagine that this would work much better in a Luger, so any tips on that would be appreciated. I might also hone the breech block a bit, it's not binding or anything but the lack of side play bothers me and it could sure be slicker.

Edit: This may be unorthodox, but has anyone tried lapping compound to fit the breech block on a Luger (i.e. coat the mating areas with lapping compound, and work them back and forth)? I do it on other auto pistols now and then, but the Luger is kind of uncharted territory to me so I thought I better ask.