Possible FTL/FTF Fix
After some close examination after I received the GSG 5 back from ATI, I would see a fairly obvious gouge in the feed ramps-rounds always had a gouge in them, and I figured the feed ramp was slamming the round about in he chamber.. I used a Dremel with a round polishing attachment (don't use the conical one nor any polishing compound) and gingerly polished out the gouge and rough edges in the ramp. I more than likely fixed the problem before I sold off the gun. As always, take your time, and do this at your own risk.