How it’s made- CO2 cartridges

I made a reusable one once. I drilled a small hole in the side on the CO2 tank, soldered a bike valve in the hole and cut a hole in the plastic cover of my hand gun for the valve to stick out. Works great. Just remember to remove the valve inners ( stem) from the valve before you solder. It will melt lol.Keep a small hand held bike pump in ya pocket and you have a limitless air supply.