i just picked up a c 93 for $400 and the guy i got it from had only fired 150 rounds through it. i checked the bolt gap and it was at .08, so i bought some plus four rollers and after installing them the bolt gap was at .04. am i to assume that this gun had 0 bolt gap and that .08 rollers were already installed ? i reinstalled the rollers it came with and the bolt gap was back to .08. i took it to the range and ran 200 shells through it. i had 7 or 8 fte in the first mag and several more in the next mag, some of the brass had the neck of the brass pinched at the shoulder of the casing and after 30 more shells i had no more fte and gun worked great but when i got home i checked the bolt gap and it now is .06, what can i do to fix this? any help please ? the gun's serial number is in the 7300's.