I keep running into milsurps that have been deactivated by welding the chamber closed and other mischief. I am now convinced that the welding heat not only damages the chamber but changes the heat treat of other parts not directed subjected to the actually weld. Been attempting to convert an early k98 mauser to a full size .22 "trainer" by reaming out the barrel. The welding hardened the barrel so much even a carbide bit couldn't cut it. Finally had to "heat treat the barrel to soften the weld metal so the pilot drill could get through it. Even then I had to use a boring bar to recenter the chamber end as the weld still forced the bit slightly off center. Even the receiver ring seems way too hard even though it appears perfect in every way. Just a heads up if you ever have to deal with similar situation.