They countered the recoil of the projectile by firing a mass of buckshot packed in grease backwards ... of another identical cartridge as a counterweight charge and the gun system being mounted ...

On special occasions he would bring out a handful of old government-issue ammunition and we would have a go at firing the fabled gun. About eight out of 10 of these old cartridges would fail to fire.

He added that he used the industrial tools to make the guns and cartridges and the trays to dry the gunpowder. Yamagami experimented both at home and in a mini-vehicle he owns. He said he took ...