The Czech gun making industry is legendary for quality and reliability.In the late 1930s, Czech weapons designers were working on a weapon that would become just another submachine gun, but before World War II exploded they planned on fielding a 9mm light support weapon in the ZK.383.
Traditionally, armies of the 20th century pursued support weapons that fed by belt or large capacity magazines chambered in a rifle caliber. However, the designers at the famous Brno manufacturing center saw value in a full-auto pistol caliber shoulder arm as battlefield support weapon.
The ZK.383, firing from a box magazine located on the receiver's left side, had a trio of features that pushed it into a class somewhere between a standard submachine gun and light support weapon. Czech engineers unusually built into the ZK.383 a changeable barrel, bipod and variable rate of fire.
While bipods can be added to any shoulder arm, the one affixed to the ZK.383 was purposeful. Czech military tactics believed there was a place with a dual purpose weapon built on a 9mm cartridge. To fire as a light machine gun, the ZK.383 would utilize the bipod (mounted midway on the barrel heat shroud) and put down a stream of fire of 500 rpm.
The rate of fire was achieved by adding a small weight to the bolt group in the direct blow back weapon. And when the ZK.383 was deployed as a submachine gun, the weight was removed resulting in a rate of fire of 700 rounds per minute.
Additionally, Czech gun designers knew that sustained periods of fire would degrade the barrel of the ZK.383. And like light support weapons, the ZK.383 was created with a quick change barrel. The barrel lock and release mechanism for the ZK.383 was located near the muzzle, directly at the base of the front sight assembly.
The ZK.383 magazine was canted up slightly to improve feeding and ejection of spent 9mm brass. The weapon was also comprised entirely of machined parts, resulting in a well made and accurate small arm. Most of the ZK.383s used during World War II ended up in the hands of the Waffen SS and was used by nations like Bulgaria and even Venezula for many decades after World War II.