Coil Gun Charging circuits?

Ok so i made this coil gun using a camera flash circuit but im using 450V caps so the circuit only charges to about 330V how would i step up the voltage in a cheap way. Buy another camera circuit or build one? If you need any more info just ask and thank you.

How about a nice voltage multiplier?

I think that could give you the desired extra voltage, at the expense of longer time to charge.