I've got a little golf ball beastie I made as well. My first thought was why do the welded breech, but I forget that not everyone has the background or access to tools to drill deep blind holes. (One of my former customers builds full scale Civil War reproductions) I only shoot mine with (2) 35mm film canisters full of FFF and it makes one hell of a boom. The trick, at least for mine, is to pack several wads of newspaper in there tight before adding the golf ball. The thing sounds like light artillery going off. I also have loaded ping pong balls with silicone and "patched" them using damp terry cloth. You never see them leave or land. I'll try to remember to post up a pic. I have to admit the stories in this thread had me chuckling. I can't begin to tell you how many times I've had the Wile E Coyote look on my face with that thing (and the s**t-eatin' grin that goes with the big BOOM)