could be LPR or solenoid.
can you take the back plate off and see if it comes out the back? if it is severe, it I would think it is a LPR leak.
Try replacing the seal on the LPR piston.
TEAM METHOD - D.O.G.'s Boy's
Custom A1 fly collector (Always looking for Angels)
WANTED: Blue and Green angel A1 FLY grips
Wanted - Angel A1/SB/AR:K parts and markers broken or working condition.
Still playing for you DAD (6/10/57 - 11/17/06). We all miss you.