Iya I did a quick calculation for a 12.7mm (1/2") dia piston the area is pi R2 -sorry cant type pi radius squared- anyway its 3.14159 x (.25x.25) which is 0.1963493 square inches muliply this by 300 psi and you have 58.9lbs or about 26.6 kg force applied to the piston this would be fairly easy to load I assume you could have a bit more than this. Also I know some Pneaumatics have a switch so you can load and or fire on low power but if you load on low then flick switch to high you still get full power on firing, maybe your friend has devised a better system to this existing one. ?
Regards Peter
Regards Peter