Empty Capacitor Bank

It should work the same but it has better specifications, so if some marginal design depends on poor performance, this part might perform too well..

This circuit has many issues and is not well suited to charging a large capacitor bank,  A voltage multiplier requires an AC input, so in the purpose of a coilgun, I imagine you ultimately want to power this from batteries, it would require an extra conversion.  You are on the right track with a DC-DC converter.  Your topology is of the boost type converter, but you would realize better performance from a flyback type (transformer) converter and this would isolate the power components (mosfet) from the high voltage side.  Also if the bank is large, use a soft start ramp up to reduce the inrush currents as the capacitor bank will behave almost as a dead short across the output when it is discharged.  If you are looking for a quick dirty way to just charge the bank to test the circuit, just salvage a photoflash unit (even from disposable cameras) as these are typically designed for 330V output and most use a cheaply made flyback converter.  Be warned this is not a good long term solution as they are designed for a short duty cycle (especially the ones in disposable cameras), and the power components are not designed to operate more than a few seconds at a time before a cooldown period.  But if you are just trying to test a concept....

Alright, so what your saying is that the current design that I have does not work. I am charging the capacitors from a 9V battery power supply. I am very new to this hobby so I am very ignorant when it comes to certain converters and such, I am appreciating all the help. Ill draw up a new schematic and I would be grateful for another proofread.

This is what I have come up with...

I Do not have any capacitor values on this because the program was for designing PCB Boards, I used this schematic as a reference.

Q1 is an IRF730, Q2 is am MPSA44

Ill use the same resistor capacitor and a similar Diode unless stated otherwise.

I am not familiar with the symbol coming off of R7

Also, in the reference schematic, there is T1 going directly into R5, I routed T1 below R5 in my schematic, is this correct?

Before building this I very strongly recommend that you simulate it. LTSpice is a free download and can easily cope with this circuit. Unless you are going to do a LOT of maths you can't tell what it will do unless you simulate. It's a lot cheaper and quicker than building it.

MK