Two fold mod ....
These type valves being similar to others using Throat pressure at time of poppet opening to also assist getting valve shut.
If you have faster / easier pellet or slug break away or even more cork in bottle tight & slow to break away the amplitude & pressure that is harnessed in getting valve closed changes. Differences in throat pressure as well time any given pressure is present will alter closing speed and therefor dwell.
By choking the flow downstream of poppet yet before the actual barrel you create a more consistent back pressure value within throat of valve which I've found in past years of R&D will lower the ES value shot to shot. You are creating sonic choking at a certain size ( pending pressure ) having the greatest expansion of the compressed air happen post restriction within barrel.
All My own R&D has been with conventional hammer knock open poppet balanced valves, tho gas dynamics ( Pneumatics ) stay similar in cause & effect best I know & understand.
The above is proven to be factual and test data supports it ... now a SPOOL valve we're going to assume the physics remain intact until testing supports something different.
OK here we are about 6 weeks later ... tad bit of fiddling has been done within the actual valve poppet, seat & transfer path areas in the first 3 weeks or so.
Early on had made a tapered transfer insert, fitting it within the space of poppets seat to exit where barrel thimble inserts. @ .900" distance.
Taper was from .340" ( same as throat & existing transfer path ) down to .250" at exit. NO POWER LOSS and muzzle report quieter !
Next mod a few weeks later was too open up the bleed hole on poppets head by @ 10% This was taking the existing .035" hole up .002" to .037"
Doing the math on AREA it only took .002" adding the @ 10%
Reason here was to get a tad faster fill on backside of spool valve piston speeding up the closing cycle just a tad & figured all things relative @ ( 10% )
* This mod cost me just a tad in power/speed requiring @ 35-40 psi more pressure for equal power ... Very minor IMO
Tad bump on reg to @ 1250 from a previous 1200+ and muzzle report is quieter again .... YEA WE'RE SAVING AIR !!! while rifles sounding a lot snappier.
Now shooting the EPOCK these past 3 weeks as set & loving it ... Had yet to see where too far was in chopping the dwell down further ( Mechanically )
Had fooled with the electronics dwell setting and found much below setting @16 valve function became sketchy. so left it on factory default 23
TODAY pulled the valve block/manifold and added another bit of restriction to the transfers exit area now having the taper go from .340" to .220"
Guess what .... No power loss !!! and quieter yet again. So were throwing JSB 44.75's at 915 fps on @ 1250psi and running a mags worth ( 22 shots ) across the chrony station with an ES on all 22 of 4 fps or +/- 2 fps.
While this is a .30 cal, all this fiddling is in anticipation of barreling this beast in .22 cal or maybe .25 hopefully this summer ( Waiting on SKOUT )
