Well i decided to take my Qb79 apart to reblue my maintube because it was done crappy awhile before this then i seen that my valve stem seal was crusty so i got a new one and now that i put it back together the first time i shot it was in the 650fps which was much lower then before. Then i took it apart cut a longer poly tube and tefloned it for a nice tight seal and before it was shooting gas out the sides aswell i test shoot it and it seemed alright so i went to chrony and got 540fps. I did do 2 things, i made the valve spring lighter, and took out the peircing unit that is meant for the QB78. Not sure if one of those is the cause. But before all this i was getting 750+fps. With 14.3gr. All the mods ive done is the poly tube, Bolt mod, and lighter valve spring.
Any help would be grateful.
