I have the PML 3" Bull Pup with the piston ejection. Great kit BTW. Anyway just wanted to get some feed back on the fit of the pistion0 I know some of you guys coat the piston with thin CA and sand. Is this necessary or should I just the piston "as is" and sand it until it slides smoothly inside the air frame? I was wonder how the fit of piston changes as the humidity changes? I know there have been issues with card board tubing. but do those issues apply to QT under similar circumstances and weather conditions?