So I just got my upper yesturday. Its a Stag flattop. I havent gotten a chance to shoot it yet. But I did cycle through about 30 rounds. I just put the rounds in the magazine and pull the charging handle each time. I dont know why I did it, but I just wanted to mess with the rifle for a bit. I did notice that there was a couple of times when releasing the charging the handle, the bolt would not fully close. I would have to use the assist thing to close it. Now I just broke the rifle open and saw this. It looks like the tips of the bullet took off a piece of whatever you see there. I looked at my other brand new uppers, and didnt see it there. I cycled through some Wolf and some Remington .223 rounds. Here is what I see. Is there something wrong?