Some Eastern Bloc countries have restrictive self-defense laws that prohibit bullet firing handguns but allow less lethal weapon systems such as guns that shoot solid rubber balls or paintballs filled with capsicum (pepper spray). Once such company that produces these guns is the Hungarian firm Keserű.

They make a particularly interesting rubber ball shooting gun called the Dragon which resembles what I imagine the mutant offspring of a pump action shotgun and under-over shotgun would look like.
The Dragon is powered by a .380R blank cartridge (the “R” is for “Rimmed”), which propels a rubber ball which is 18mm (0.7″) in diameter.
What I find fascinating is that the chambers are removable. To facilitate fast loading, instead of loading the ammunition components, the operator loads pre-loaded chambers, much like you would load a magazine. I suspect the local laws require the projectile and propellent to be loaded into the chamber separately, so innovative the locals came up with this duel chamber system.

18mm Rubber Balls and .380R Blank

The pump mechanism is used to lock and unlock the chambers. Its trigger makes use of a double action striker fired mechanism.

While this system has nowhere near the power of a self defense handgun, it can generate considerable energy. I am not sure about the Dragon, but the Omerta-T, which uses the same ammunition, generates an impressive 95 ft/lbs of energy. This is slightly lower than a Standard Velocity (sub sonic) 40 gr .22 Long Rifle round. The rubber ball would hurt like hell. I have a high pain tolerance and I can assure you that a less than one foot pound plastic bb fired at point blank onto bare skin is very sore. I know I would much rather be hit by a taser than a rubber ball being propelled by 95 foot pounds of energy!

Omerta-T with its magazine style removable chamber.

A Tacti-cool Dragon

Hat Tip: Дмитрий Кочетков