being pig-headed, i've been watching videos and mulling this over for 3 weeks, and my conclusion is that maybe there ARE dings on the muzzle*, and that lapping may be the solution**, or at least it's cheap enough to try without a big outlay of cash. so today i got some brass screws and valve lapping compound and ordered up a 45 degree brass crown lapping tool from brownells https://www.brownells.com/aspx/search/p ... 53&pid=679
, which is expected to arrive by monday. so the question in my mind is, try the screw head first, or wait for the tool to arrive and start with that?
* how they got there inside that flash hider eludes me
** i have "reasons" to believe this, or maybe i'm just rationalizing. A: the sight adjustments i've done are opposite what i think i'd need to correct an out-of-index barrel, and, B: i tapped a .308 bullet into the muzzle just enough to engage the rifling, and the marks it made are noticeably bigger on one side than the other.