can any one tell me how to remove my brake from a century arms L1A1? the brake is 1 1/2" long and has 3 ports on each side. I have been told it is pinned on and i know it is threaded as well. my problem is that i cant see any pins and it wont just unscrew. does any one have any experiance with this kind of gun? also, i would have to drill out the old pins correct? thanks for the help!