>>64411529
you need some serious ventilation for that, you'll have some sort of lung or kidney cancer within a decade if you breathe every bit of every round you fire. Also the projectiles would be a problem, you're either shooting lead or expensive downloaded copper solids, lead would need a gentle trap that doesn't deform the bullets much as it stops them, so you're not inhaling aerosolized lead particles.

You could build one yourself, legally, with a bit of documentation, tools, knowledge and money. If you don't care about cancer then what the fuck would laws matter to you?

There's also pic related, which I found you know hwere. It's a goddamn good looking gun. The real answer is this though >>64411562 Air guns are the answer that doesn't kill you or get you buttfucked in prison.