Well, I found a simple online calculator to get barrel length, though there's definitely better programs out there:
http://www.ken-zoe.net/Potato/
3' combustion chamber is nuts! Are you making a howitzer???

Just finished drilling and tapping holes into a 12" x 2" chamber, 48" x 1.5" barrel spud gun ...

New to spuds and caught the velocity bug. Anyways, a few questions:

Are differences between air and hybrid significant? Could I launch a >1 lb spud at supersonic (1116fps) with air given a $300 budget? Or do I need to hybrid for anything heavy supersonic?

Still browsing the guides section; any ...