Thanks to the previous work by fellow member rsterne, took his info and applied it to .22 Hammerli Pneuma.
Started out plugging 5 of the 6 valve holes ( This valve took 4-40 size grub screws BTW )
JB weld up the space between like Bob had done
Next having just the valve body in hand screwed it into main tube snug, then drilling down from the transfer passage opening up the remaining 6th hole to .165" being same size as the transfer passage. With a dremel tool slightly flared the hole outward into throat area behind seat.
Having pulled the seat earlier found it's I.D. hole @ .162" which was IMO going to be too small with the bigger passages down stream.
So ... gently held it in the lathe jaws carefully drilling it out to @ .175" which leaves the poppet a sealing margin @ .055 total ( .0275 contact width )
Drilled out the face of body with 3 holes as Bob had done using .125" diameter at the 20* inward angle converging holes just under the spring retention cup.
Reassembling rifle for a few test shots changing nothing in hammer tension from previous strings headed over to the Chrony
** As spring tension was set from earlier, rifle was shooting CPHP 14.3 pellets @ 835 fps for just a tad over 22 ft lb power.
( @2000# in tube )
** After valve mods with SAME settings, rifle was shooting CPHP 14.3 pellets at 965 FPS for just under 30 ft lb power
( @2000# in tube )So indeed valve responded to some massaging and flow management
Now why this is all fine and dandy, quite likely rifles a bigger air hog than it already was
which gets to the reason for these mods with no interest in efficiency numbers quite yet
REGULATION on the way
... Wanted to get the preliminary mods that would have rifle making the @ 30# power I was after at the @ set point pressure regulator will be used at. ( Actually @ 1800# ) which will have valve opening easier yet ... then allowing less spring pre-load to be used lowering dwell and air use
** Now we wait for the Huub AT-44 regulator from the Netherlands to arrive so we can finish up and see if concept = reality
Stay tuned ..........