hmm, i like it, nice and compact but when firing a self propelling object, its probably gonna spin a bit and then come back and nail you in the face. this is a great idea if mayby you could rig 3 or more fins to the tail end like a model rocket. ive punctured a 12g co2 cartridge....... not fun.........

i myself am a noob and havent built anything, but i was wondering if anyone has ever tried a pickle. i figure it would fit in 1.5" but im not sure