Mp5 sd6 second day of buying it I striped it and replaced every single part with upgrades.then had to cut the spring as it was firing at 5.56fps.still my fave rifle,never let's me down.since then iv added a front drop down hand grip,strobing flashlight, lazer and a scope.
I have a gbb mp5 and for some reason it now only fires upside down.I have stripped it soo many times but after a couple of shots it goes back to only firing upside down
Any suggestions would be gratefully received.