He'd do a hell of a lot better with less caps closer to the launcher. Does he really think he's getting the full 4/10th of a Farad's worth out of that stack?
You mean from the inductance in the wires? I could see that, I know that bypass caps on digital ICs are best placed right at the power pins, so they can capture fast rise or fall time spikes properly.
Partly the resistance and inductance of the leads, partly due to the fact that if the pulse width is longer than the time the slug is in the barrel then you're just pissing the rest of the energy away in a massive arc, which is what we see coming out of the barrel.