You'd better be careful. The Department of Homeland Security would never allow the proliferation of such dangerous technology at home. It will soon be a viable threat to all forms of paper armor everywhere. They are watching you.
You do need HV to make a coilgun. The inductor's rise in current is proportional to the voltage on its terminals. At low voltage the current rises too slowly to be useful. If you had a lower inductance then of course the current rises much faster for a given voltage, but a one-turn coil would not produce a useful force.
The current driving capabilities of the source is only part of the requirements.