The ZK-383 is a Czech submachine gun.
The ZK-383 was designed by brothers Josef and František Koucký and is unarguably their most well known firearm. The weapon began production in 1938 and was exported to many smaller European countries since then, with most of the guns produced being supplied to the Waffen-SS of Nazi Germany. The weapon continued to be produced, albeit in small numbers, during the post-war period, with Bulgaria continuing to import the ZK-383 up until 1970, four years after production of the ZK-383 had ended. However, by that time, the ZK-383 was slowly becoming obsolete, and was being phased out in favor of smaller and lighter submachine guns that fulfilled the same purpose, such as the Škorpion and the Sa vz. 23.
The weapon uses blowback to fire its rounds. Interestingly enough, the ZK-383 was designed to be a squad automatic weapon instead of a submachine gun despite firing a pistol-sized cartridge. For a submachine gun, the ZK-383 was heavy, but robust. The weapon unusually features a bolt weight; something not many other submachine guns, or any gun of that matter, has. The weight could be removed to adjust the rate of fire of the weapon from 500 to 700 rounds per minute. What was even more unusual was that military versions of the ZK-383 featured detachable barrels, rifle-type sights and integrated bipods, making them more akin to light machine guns like the MG 42 instead of a submachine gun.
Police variant; lacks a folding bipod and detachable barrel.
Post-war production variant; lacks a folding bipod and detachable barrel and has a forward facing underslung magazine.