Wondering the best way to switch high voltages. Building a mini rail gun and trying to figure out how to implement a fast switch. I've seen it done in camera flash circuits with neon lamps. Not sure how to implement this.
Similar to a camera flash circuit. Probably use a 9V battery and step-up transformer to around 300V. Using 330V caps. The current will be relatively small unless there is a better way to do it to get more current from the charging circuit.
A good way is with an SCR. Pick one with a sufficient voltage rating (at least 400V in your case) and at least a 10A current rating. A small current to the gate will trigger the SCR to rapidly conduct and discharge the cap. The SCR cathode should be grounded and the load connected between the cap and the SCR anode.