It kind of depends who is asking - it's either
1. Target shooting (after all, it's just a .22RF semi auto firearm - same as millions of others out there)
2. Because I want one, and the law says it's fine.
Excellent - if you need a hand with any of the research, just let me know. I have thin+ thick cylinder calculations to work out just how thick the steel needs to be to contain the bang. Personally, I like to multiply that by 5-10 times to make me happy to stand next to it when it's being fired.This is great. Once I finish my current project, I'll Now be building a cannon next. Thinking of making it so that it fires golf balls. (not researched it yet!)