anybody know how to change em? got a link or something? i replaced my cz52 barrel with a federal 7.62x25 threaded barrel, but i hear that the rollers on the federal barrels are weak so i bought some spare rollers and cant figure out how to swap em out. i'm also having trouble replacing my firing pin because i bought a model that is a heavy competition model pin and the instructions vaguely say i need to modify the extractor with a file, but i might just exchange it and get a normal hardened firing pin. any advice on either modification would be helpful though, i know a few of you guys have cz52s, somebody must have done this or know how to do it.