Came back from Oregon EFT with a rifle that intrigued me. Typically don't fool with this brand but the design and lay out was speaking PESTING BEAST !!! as trips up north to ground squirrel hunt in open alfalfa fields may save packing air bottles or trips to the truck for more air, so we took the plunge and brought it home to fiddle with / modify etc ...
Did an initial power test at @ 150 then 200 bar ( Unregulated design ) and found it having just modest power shooting a JSB King @ 840 fps for @ 40 fpe. The muzzle noise was LOUD !! and hammer bounce very obvious as well. Starting to see the light we have work to do !!!
So .... onto the bench it goes and soon becomes a pile of parts & pieces. First off the typical Turkish PCP shroud silliness, yea it has a nice big volume shroud over the 15mm barrel, but does NOT contain an air stripper, muzzle set back spacing or any miens for the air exiting muzzle to use the shroud for silencing the bark ... Face palm time
Now with 3 bottles and 1425 cc of air on board the design to tie it into a single delivery at valve was done via small drilled passages on the side by side manifold up front, so passages got opened up there to be freer flowing. Valve gets a seat clean up/re-profiled with the transfer path from barrel down to valve opened up to @ .190" We change out the proprietary oddball fill fitting to "Foster spec SS HUMA fill"
Next up the Trigger mechanics which surprised me as I expected the Evanix style snag sear seen on previous Kral rifles / turkish PCP's. This trigger an actual adjustable sear and drop away hammer holding pawl .... Nice. The actual two parts that make up the SEAR were Hard steel with the remaining link/toggles being cast aluminum. The contact areas of links & toggles smoothed up and sear/s get ceramic stoned to crisp & smooth edge with everything getting heavy moly upon assembly. ( Picture shows configuration assembled on outside of receiver )
* Needed to do this, figure it out as I had failed to take a picture prior to disassembling ... oups.
Barrel gets a lapping / waxing with leade & crown redone. Pushing pellets threw feels a lot better than as delivered. Snug choke tho and spend more effort there lapping to free it up some.
After doing my thing inside it all gets reassembled with fresh o-rings and sealant where required. Over the chrony with exact same settings power has come up @ 40 fps and the hammer bounce is still a problem
Dig threw my stash of springs finding an idea replacement that is a tad stiffer in spring rate and a tad shorter. This works out to now have hammer in Free Flight of about a quarter inch.
Fill back to 150 bar and dry fire a few times ... SNAP !!!! One hammer strike and Zero bounce !!! Over to chrony again and the same King pellet is now sizzling along at 960 fps making 52fpe !!
While muzzle report is still Loud it is telling with no bounce the guns acting far more efficient even with the greater output it is now producing.
Remember this ... Shroud does nothing issue, lets fix that !!!
Making an air stripper that threads onto barrel having 1/2-20 Female/Male ends we lengthen the barrel at muzzle. Then fabricate a Delrin extension to cover the stripper retaining the same Shroud I.D. dimension and extending to reuse the thread on end cap with its 1/2-20 LDC mounting thread. * Barrel length increased by @ 3 inches. Yes it took the sharp crack to a muted sound, tho still in no way back yard friendly, but much better IMO.
Scope is a Optisan / MTC Viper 8-32x56 on Med rings that has objective bell @ 3/32" off the shroud .. it clears but not by much.
** Accuracy and testing is going to wait as I've got weed eating and yard work to do while we have this temprary cool weather spell.
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