Originally Posted by Munaro
I have a G&G MP56D6, Its a good gun, very accurate, good ROF. But like Slow said, change out the Piston or you get like a 10 - 30 FPS variable. and the reason for this is the piston itself isn't all that well built, and the O-ring is waaaay to small for the piston.
Really I've chronoed my SD5 and i got a -/+ of 7 at around 375 fps not saying the piston/cylinder assembly are good but it's not as bad as you claim