Originally Posted by
Pneumagger
sear stop not really needed and won't solve this problem. that is not why it chuffs. I've found 3 solutions to the chuffing problem...
1) More air flow - allow the trigger to open the 3 way more or up the pressure
2) add more shims to the ULT
3) replace the ULT with an the RT on/off
However, shingo... If you aer running co2 to that classic it will shortstroke. If you are firing very fast... you may outshoot the valve hardcore. What on/off do you have? For classics, I've found the best on off is the RT with a quad oring.