KS-23

The KS-23 is a Russian shotgun, although because it uses a rifled barrel it is officially designated by the Russian military as a carbine. KS stands for Karabin Spetsialnyj, "Special Carbine". It is renowned for its large caliber, firing a 23 mm round, which in standard usage equates to approximately 4 gauge, making it the most powerful shotgun in use today. By comparison, the Nudelman-Rikhter NR-23 cannon uses a 23 mm round, as does the ZSU-23-4 self-propelled anti-aircraft weapons system.

History
The KS-23 was designed in the 1970s for suppressing prison riots. It was created by TsNII-Tochmash, a key Russian weapons developer, for the Russian Ministry of Internal Affairs (MVD). The barrel for the KS-23 was made from 23 mm anti-aircraft gun barrels that were rejected due to manufacturing flaws. These rejected barrels were deemed to be acceptable for the lower stress of firing slugs and less-lethal rounds, and thus were cut down in length for use as shotgun barrels. The KS-23 began to see use during the mid-1980s by several MVD forces. During the 1990s, research was made into improving the original design to make it usable in confined indoor areas. Two prototypes were proposed, the KS-23M and KS-23K, although only the M version saw use. Today, both the standard KS-23 and the KS-23M are in use by Russian law enforcement.

Ammunition
The KS-23 was created with the capability to fire several different types of ammunition, listed below:
 * "Shrapnel-10" buckshot round with 10-meter effective range
 * "Shrapnel-25" buckshot round with 25-meter effective range
 * "Barricade" cartridge with solid steel projectile able to destroy the engine block of a car at up to 100 meters.
 * "Wave-R" rubber less-lethal cartridge
 * "Bird cherry" tear gas grenade with CN agent
 * "Lilac" tear gas grenade with CS agent
 * "Star" flash-bang round

Later, two add-on muzzle mortars were produced, the 36mm Nasadka-6 and 82mm Nasadka-12, bringing with them several new ammunition types:
 * Blank grenade launching cartridge to be used with muzzle mortars
 * 36mm "Cheremukha-6" tear gas grenade
 * 82mm "Cheremukha-12" "high-efficiency" tear gas grenade for use on open areas

KS-23M
The KS-23M includes a detachable wire buttstock and shortened barrel, as opposed to the fixed wooden stock on standard KS-23s.

KS-23K
The KS-23K is a redesigned KS-23 that features a bullpup layout. There is also an extended box magazine that holds 6 shells instead of the 3 shells seen on the other models.

TOZ-123
This civilian version features a smoothbore design, making it more similar to a traditional shotgun, and is chambered in standard 4-gauge.