Chamfering the breech? Been there, done that!
My brother bought a couple knockoffs of the Browning semi-auto 22 on sale. They were right pigs, and jammed more than they fired.
I took a look at them, and they both had very sharp edges to the chambers.
I ended up using a cheap little battery powered fish hook sharpener to put a nice smooth radius on each of them. No troubles since!
Not the preffered tools (rather use a Dremel, or a set of jewellers files and some stones) but worked well enough.
If I recall correctly, I used about a 1/16 inch radius, more or less, just along the edge nearest the feed.
I had an AR7. Cheap, light, and jammed a lot if it got at all dirty. Worst thing about it was that you could bump the mag release when shooting, and the mag would hang in the well for an indeterminate time, then drop on the ground. I spent a lot of time backtracking, because of that.
Cheers
Trev
