I'm here to say the same thing.
A 45 ACP round in a Colt 45 Automatic pistol is 600 foot-lbs, or 450 joules, and it'll do more to steel-backed plywood than just dent it.
No way the projectile is ending up with 1800 joules in kinetic energy. Perhaps that is what the capacitor bank starts with, but that's not what the projectile ends up with.
Try to be charitable about the 3 million joule thing. I work on a NASA campus that has a regular old utility transformer outside labelled 23,000 Kilovolts (and it's not).
Mistakes are made