Janes reports that Russian firm KBP are now producing a tactical version of their MTs 225 revolver shotgun:

The MTs-255 tactical shotgun is a 5-shot weapon and is designed around the revolver principle. The cartridge cylinder swings out to the left for loading/unloading. It can be fired either double-action (a long pull of the trigger both cocks and fires the weapon) or the hammer can be manually cocked for single-action firing. A heavy duty, single-strut metal side-folding stock is fitted, which pivots around a conventional style revolver pistol-grip and lies alongside the right side of the gun when in the folded position. Sights are described as ‘open’, but a length of Picatinny-type sight rail is fitted to the top of the receiver for the mounting of other sighting devices. The butt-plate, pistol-grip and fore-end are all constructed of high-impact polymer for durability and corrosion resistance.

The original MTs 225 was introduced as a hunting gun back in 2000. It has an interesting design. The benefit over semi-autos would be its double action revolver reliability.

12 guage

.410

Photos from Tozman @ Shotgun World Forum.