I've always fantisized about using the top part of a c02 canister (12 gram) for a bowl. Well let me tell you, it works! I had to use a hand saw, because nothing could clamp it down good enough for the power tools. Here's a visual. Im talking about cutting it about .75 inches from the left. Also, the hole the airsoft or paintball gun puts in the end is just small enough for smoke to go through, so you dont need screen.