1903a4 receiver tearing up tap...
So I recently bought a 1903a4-gery built off a reclaimed drill receiver and found that the rear bolt tap wasn't done quite right. I took it to my gunsmith to have it redone proper and the receiver chipped away the tap. He'd had the tap for awhile and figured it was just at the end of it's life and ordered a new one. When he tried with the new tap the same thing happened. He's now going take it to his machinist and see if he has any insight.
Has anyone ever run into this issue?*
Maybe dangerously over-hardened?
"1903a4-gery built off a reclaimed drill receiver"
Warning bells are ringing here. It sounds like the receiver is excessively hard, even glass-hard (which means DANGEROUSLY hard), in an area where it should not be. There was a history of early 1903 receivers being withdrawn because of faulty hardening, making them brittle. Is it possible that this is such a faulty (over-hard) receiver that someone has creatively "recycled"?
Check out the number and the number range for the brittle receiver problem, look for signs of welding, renumbering etc.
You may have acquired a piece of dangerous scrap that was not intended to be used for live firing. I hope not, but check it all.