Thanks for the feedback, those were exactly things I was worried about.

Plus I'm not too sure of the project, as I've just found out that combustion spud guns are illegal in Denmark, so I might just have to go with a pneumatic set up instead.

My first post here. I've built simple combustion spud guns and pen cannons before, but I'm wanting a good summer project and thought of a more complicated design- a semi auto spud gun. I'm not great at electronics so I wanted a mechanical system to load/reload, prime and shoot. After many, many (man...