2K1TJThanks,The limiting factor at this time is the amount of distance between the end of the pump faceand the air intake hole of the pressure tube. On my rifle, I only have approximately .130" of space left before the pump head blocksthe air intake hole. I have already lengthened this distance by 1 full turn, (still have to do a chrono test),but I don't know the thread count to figure out this amount of movement.I will take it out to the maximum distance and do another chrono test to see the results.The only other option is to redesign the valve, make it longer to use up the excess emptyspace of the pressure tube to the pump head at it's extended length etc.I'll do some careful measurements of the valve dimensions, when I get to the valve out.At this time it appears that there is only the 1-2 screws holding the valve in place,which are the ones in the steel block right in front of the trigger. I won't know for sure until I get to that area etc.Your thoughts and suggestions are welcome.Tia,Don
Here is another post on the DF IIBbl TP hole is .134" Dia,Action TP Hole is .134" Dia,Brass TP has a hole Dia of .136" x .295" tall x .356" dia,w/a step on each end that fits into a rubber "O" ring on the action and the valve,Hammer spring is 18/19#'s at max compression, (coil bound), 3.150" long, .390" dia O/S dim, x .300" I/S dim, with 15 coils.Hammer weight is 876 grains x .760" diaMain valve is 2.520" long x .765" dia, and has a TP hole of .136" with an inside spring witha plastic pointed cone and a 2 piece shaft, metal shaft fits inside the poppet seal.See photos, I hope.Tia,Don