KS-23  The KS-23 is a Soviet shotgun, although because it uses a rifled barrel it is officially designated by the Russian military as a carbine. KS stands for "Karabin Spetsialniy", "Special Carbine". It is renowned for its large caliber, firing a 23 mm round, equating to 6.27 gauge using the British and American standards of shotgun gauges and approximately 4 gauge using the current European standards (based on the metric CIP tables), making it the largest-bore shotgun in use today. The KS-23 was designed in the 1970s for suppressing prison riots. It was created by TsNIITochMash, a key Russian weapons developer, for the Russian Ministry of Internal Affairs (MVD). The barrel for the KS-23 were made from 23 mm 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. The KS-23 was created with the capability to fire several different types of ammunition, listed below:  Later, two add-on muzzle mortars were produced, the 36 mm Nasadka-6 and 82 mm Nasadka-12, bringing with them several new ammunition types:   The original KS-23 was developed jointly by NIISpetstekhniki (MVD) and TsNIITochmash in 1971, it was accepted for use by the Soviet police in 1985. The gun has a barrel length of 510 mm and an overall length of 1040 mm. The KS-23 has an underbarrel tubular magazine capable of holding three rounds, with one in the chamber giving the gun a maximum round capacity of four. The gun's effective range is 150 m. The KS-23M «дрозд» (Carbine, Special, 23 mm, modernized - project: "Drozd" > "Thrush") was developed on the base of the KS-23.