There are various little niggles, most cured by keeping the regulator and the internals all lubed up with Dow 33. The main fault to look for is the cocking rod can get deformed at either end, the other thing to look for the piston has a plastic collar on it (it is meant to be split) a touch with wet and dry glasspaper will ensure that it moves easily between the piston housing and while talking about the piston housing sometimes this can crack but it is rare, the piston its self is suspect from a longevity point of view, get a rocket piston from Planet.