Had a close look at the barrel on mine...no such marks. Looks like a lathe chuck jaw to me.....
Mine was initially somewhat fussy, and did not group to expected potential...re-worked both ends and seems to like pretty much anything I feed it now...very close call as to what shoots best, very slight edge to the 10.3 JSB still. Have yet to order any Meisters....need to get on that.
Al