This is a Spikes upper, BA Premium 12.5" 6.5 grendel barrel, Nitrided Brownells 6.5g "type II" with .136" bolt face depth. Maybe 200 rounds total. I did fire 80 rounds of steel cased Wolf on the last trip and also got a stuck round, but it came out pretty easy with a cleaning rod. (I've had to pry rounds out with screwdrivers and plyers before, there's no way that caused THIS, though "this" could be causing something bad?) I honestly can't recall if I ever closely inspected the barrel before assembling, I mean machining from the factory is what keeps popping into my mind as possible cause. I'm wondering how under normal circumstances this damage could even happen. Anyways.. anyone seen any marks like this before? Thoughts? Second pic is taken from the ejection port..