Flatline SLOW recharge

I just rebuilt my 3000 flatline and it is working good except the recharge rate is terrible. I have it on a bushmaster 2000 with a CP reg and at 600 psi input it takes 1.3 seconds to recharge back up to 600 after I take a shot. If I fire 4 shots in a row the last one is rolling out the barrel. Did I do something wrong when I rebuilt it? I got it from a trade and it was pissing air like a mofo, anything I should try or do I need to send it to AGD

spring pack was in bass ackwards .... My bad :D