I was a little off. I was looking more at the combined law, as here:
https://en.wikipedia.org/wiki/Ideal_gas_law

My vague memories of chemistry had them the same.

The ideal gas law is probably more relevant to this, as it considers changes in pressure, volume, and temperature, all of which happen. You'll probably have to do it the same way I'm looking at when I someday get to more complicated projects--you measure your velocity, calculate your pressures and v...

I was looking at copper for a couple of designs floating around in my head, but when looking at a decent sized gun(would want 1-2" barrel, and reducer to go from that to a 2-3" chamber/valve), the price of copper parts made me go :o Before I go looking at making my own parts oit of aluminum and braz...