Ok I have a SGL-21 here with about 300 trouble-free rounds through her. The bolt carrier rail on the right side is a bit thin, and it really bothers me. I sent it back to Arsenal and they sent it back and said the rifle is functioning fine. They did offer to replace the rifle though. I have another SGL-21 that has beefy rails on both sides, so my question is: Should I sent it back or is this perfectly normal?