As someone that has screwed up metal parts over and over.... it looks like you still have material, and may be able to hand-file your bevels to better match. They look smaller in diameter than the mauser flats, so if you file them down they will get bigger as you dig into the cylinder. In fact, if you only do the diagonal sides that may help even stuff out. Also.... JB weld can smooth out grooves like this. If you want to disassemble it, apoxie sculpt sculpted to fill the gap and then unscrewed, it will harden in the correct shape... idk, my vote is some hand filing to make it less noticeable. You may be able to lessen the unevenness!