O-ring seal for the poppet is not needed, and will blow out in any case. Make the poppet head from delrin, keep things concentric and it'll seal fine. Tone down the big wedge shape, wedges jam into the seat under pressure. BTW....undercut a delrin head with a ball end mill and face off to leave ~.020" flat on the perimeter and it'll seal super easy on a flat faced valve body.
If the striker is to scale, it'll be far heavier than required. Would suggest cutting the mass in half at least for co2 operation.
O-ring on either end of the valve body is not needed, only the pressure end of it. You're going to secure the valve body with screws, and it'll leak there....which is why you don't need the second o-ring. Need to seal the transfer port though.
Please use high quality socket head cap screws to secure the valve, and do the calculations for screw shear and bearing stress on the tube. Ask for help if you don't know how...it's easy and in your best interests to do it.
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I stick to a minimum safety factor of 3x MWP at yield strength. For co2, that's 5400psi.
BTw.....do you actually have the Lonestar Gambler in your avatar pic??? Haven't seen those in years, but they sure were FUN!! 8)
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