Hi mates in the inards of the gun by the brass bit there's a sort of ally piece shiny and in the middle of it is a flat headed screw it about 3/8 in size well mines lose so does any one know what it does should I tighten it up or leave it as it must have something to do with the air flow So please only answer thread if you know what it is (I don't need "I think answers")not on this one.please don't think I'm rude but it's my safety I'm thinking about as there's a lot of pressure in these pcp thanks mates