
You have no idea how much your first picture looks like my old coilgun.
Mind you a lot of things look the same when covered in black electrical tape.
No idea what circuit I used, I just snaffled a ton of used disp. cameras from the local chemists and had a separate charging thing I linked up to the capacitor pack.
But it had 12 90-130uf 330v caps wired up in parallel through about 2m of wire from a toy motor around a pen tube and if you got 1cm of a sawn off nail JUST in the right place in the tube you could fire it through thick kitchen foil

If you didn't, it did nothing, fired backwards or pushed it just enough to drop out of the tube.

Yours looks a lot neater in the project box though, mine had two cap wires sticking out of the electrical tape for charging. I'm sure I'd have seriously regretted it if I'd ever touched those when it was charged

580uf at 330v seriously bites.