Look for parts of a partialy shredded bumper in the body somewhere slowing you bolt and hammer down. Also make sure the bolt is not swelled by pulling the back block back and letting it come forward. If it does this on it's own and with little resistance swelling and shredded bumper is not your problem. If it doesn't look for the friction and eliminate it.
The seer plate is tight....I broke 2 of them before I got one to sit good and snug.
I completely stripped the gun down, cleaned the hells out of everything, ran everything thru a buffing wheel, straightened and aligned everything. Works better now, but is still not totally reliable when running paint.
I'm thinking that I might turn the manual velocity up a bit, and then adjust the reg to compensate. Basically, it's post tournament season for me right now, I have 3 months till the next...I have time to tinker.