If you decide to increase the reg pressure, completely degas the rifle and then you can disassemble the reg and add a spacer shim. I used a SS washer I had on hand that was 16mm od x 7.4mm id x 1.45mm thick. I first sanded off the washer burr edges on a 400g sanding block. I used a snap ring tool to unscrew the reg access cover. Rounded needle nose pliers would likely work too. Remove the Belleville washers, 12 of them, and drop the shim washer in the reg cavity then replace the Belleville washers just like they came out. Here's the stackup that I had in mine. Inner ->shim | ))(( ))(( ))((<- Outer. Tighten the access cap back down. Loosen the adjustment locknut and tighten the adjustment screw CW to loosely seat it then back it off ~1/2-turn. Add the bottle fitting and the test cap on it. If the zblock is off the rifle, install the valve assembly on the other end. Hook up to your compressor and pressurize up to ~3kpsi. Watch the reg gauge, it'll only come up to around 600-800psi. Now you can slowly adjust the reg screw CCW until you are at 2200psi or so. Give that a try. If it's where you want it, degass the zblock and mount up on your rifle. I suggest keeping the test cap on for the initial fill and shoot a few shots to see where you're at velocity wise. At 4000psi on the inlet gauge, you'll get a few good shots with the reg test cap on there. This is faster than filling the 220cc bottle to get things dialed in. If it's shooting where you want, degass and swap in the bottle. If still too low, bump the reg up CCW another 50-100lbs. If too high, degass and adjust screw CW ~1/4turn inward. Pressurize and test it again. Adjust it until it's where you want it. On the QUPB Z-block I loosen the foster fitting to degas. The setscrew in the bottle adapter fitting is a bottle isolation "valve". Degassing with it resulted in a damaged/cut
oring on mine. That setscrew needs to be loosened ~3/4-turn to allow bottle to fill.
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