maybe I'm talking out of school here, but I believe that's normal. The firing pin in the ARs freefloat. Inertia from the bolt slamming home allows the pin to slightly hit the primer. (one of the reasons it's not recommended to cycle live ammo off range) 5.56 ammo has hard primers for this reason.
As far as the scratches, it's from the feed ramps. It happens on my DPMS, my wife's Doublestars, (all 3) my RRA, and just about every new AR rifle I've ever shot. If it bugs you, you could polish the sharp edges, but it won't hurt anything as long as it's not causing it to hang up. It will also shoot out over time as the sharp edges wear.
For the charging handle being stuck--Probably the locking lugs/cam pin being a little tight. They will also wear in (I use NO lube for the first 100 rds to 'encourage' the wear process. After the first 100 rds, I clean it and put a little dab of moly lube on the lugs and cam pin, lube everything per the manual) If it were my rifle, I'd just shoot the hell out of it and have some fun. If it gives you trouble, post again....the hive mind will hook you up!