The same could be said for using a CO2 gun on a hot day, as the pressure can reach 1900 psi at 120*F using CO2.... We can only assume that the manufacturer has taken that into account, as I have never seen a report of a QB failing from sitting in the sun or a car trunk.... I'm not saying it can't happen, just that I've never heard of it.... However, I would never use HPA in a CO2 gun without a 1.8K burst disc fitted in the regulator....Bob
I'm not trying to encourage anyone to play outside their comfort zone.... just pointing out that although 850 psi is considered the "normal" pressure for CO2 it can easily be twice that without you even realizing it....Bob
Because you can't do anything about the pressure anyway, it is a function of temperature with CO2.... In theory the manufacturer should be designing the gun with about a 3:1 safety margin above the 1900 psi pressure you could get at 120*F (that temperature is stamped right on many CO2 cartridges as the maximum allowable, and bulk tanks are rated at 1800 psi MSWP).... In practice, however, that is NOT the case, as the QB79 failure at 2600 psi shows.... Maybe the engineers figured 3 x 850 psi = 2550 psi to failure was good enough.... or maybe they took into account the additional safety provided by the stock screws that fit into the block.... or maybe they just guessed.... My point is that if you use a 1.8K burst disc on HPA you shouldn't be any worse off than using CO2 on a hot day.... This doesn't apply if you change a cartridge gun like a 22XX to bulk fill, of course, because the tube in a 22XX was never intended to hold pressure, and the valve isn't mounted to withstand it.... There is a lot to consider when converting CO2 to HPA, and even the most innocent things you would never expect can bite you.... The knurled nut retaining the fill fitting on the QB78 and XS-60c is an example.... It should never be used at over maximum CO2 pressures, because the flange on the end is too thin.... QVTom did a Finite Element Anaylsis on it, and the stress diagram would scare you (it did me).... I even missed that one....Bob
Agree, the only real safety feature is the 1.8k burst disk on the output side of the regulator. So long as it works (and they are pretty reliable), will prevent a drastic over pressure inside the guts of the rifle. These older gagued on/offs have a 1.8K disk as well, but evidently that 2nd disk never saw enough pressure to blow once the regs. 1.8K disck let go.I’m just going to rebuild the regulator on the 800-850psi tank and put the rifle back to 12 foot pounds.