The double-barreled, single-trigger Baikal IZH-43 shotgun is manufactured by the Izhevsky Mekhanichesky Zavod Corporation in Izhevsk, Russia. It can be hard to nail down a year when this gun began production, but the company was founded in 1942 and it saw some use in World War 2 by Soviet troops, so it’s reasonable to assume that manufacture of the weapon started around that time (likely 1943 as is often indicated by firearm names).
The IZH is a side-by-side shotgun utilizing a barrel selector to switch between sides. By design, this means both barrels cannot be fired at the same time. It also features chrome plating for both bore and chamber to resist corrosion and standard threading for choke tubes.
In addition to custom sawed-off variations, the IZH has been offered with barrels of varying size to suit different uses: 20″ (50.8cm), 24″ (61cm), 26″ (66cm), and 28″ (71.1cm). The standard model in-game appears to be based on either the 24″ or 26″ version.
Above all else, this gun is known for its durability. Soviet dedication to simple, reliable, inexpensive designs is just as evident here as it shows in the AK family of guns. It has few fancy tricks and brings with it no special qualities, it simply guarantees to get the job done no matter what.
Picture courtesy of IMFDB.org user Mateogala.