You forgot the primer or ignition system. I am wondering if the guy didn’t use shells but went completely home-made, and if so, did he skip the primer stage and go for electric/electronic ignition.
Japan has ammo and gunpowder control as well.
Looks like it was a battery to me, which could set off a short fuse.
Wires are hanging out of his weapon.
I’m not going to give it away, but a bat/wire/blackpowder is all it takes.
When I was much younger.
Pipe electronic ignition black powder.
Worked decent enough
Fireworks are legal in Japan. Just buy some over time until you get enough powder from them.
Plenty of fireworks readily available in Japan to provide a source for gun powder.
Based on the video, the first barrel nay have misfired/malfunctioned (noise, smoke, no apparent effect). The second barrel functioned enough to fatally wound Abe at that range.
[[Japan has ammo and gunpowder control as well.]]
Japanese like fireworks. Disassemble a few, and you have black powder. An electric spark can replace need for primer.
And if he’s ex-military, he may have had counter insurgency training regarding improvised weapons and explosives
sodium nitrate +sulpher + charcoal = old fashioned gunpowder, not at all hard to make.