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

The line is called “Critical Defense” and will be available in .380 ACP, .38 Special, .38 Special + P and 9mm Parabellum.

A Critical Defense round

A common argument against hollow points is that when they are fired through heavy clothing the hollow point can clog up with fabrics and then act as a FMJ round. The Critical Defense bullets feature a hollow point with a rubber insert (same material as the Flex Tip used on the Hornady LEVERevolution ammunition) which prevents the bullet clogging up with fabric and allow controlled reliable expansion.

The idea of putting something in a hollow point to prevent it being clogged up with fabric or, in the case of hunting ammunition, fur, is not a new idea. It will be interesting to see if the Flex Tip material improves on this idea.

Another useful feature of this line is decrease muzzle flash.

For each type of cartridge and load the bullet has been individually designed for maximum performance.

Product video:

More info at Guns Holsters and Gear and Hornady.