URZ rifle and machine gun weapon family (Czechoslovakia)

URZ rifle

URZ light machine gun

Patent diagram for belt feed system used in URZ rifle and machine gun

Patent diagram for delayed blowback system used in URZ rifle and machine gun

The URZ rifle family (Univerzální Ruční Zbraň – universal handheld weapon – also known as “Plamen”, or “flame”) was developed during the second half of the 1960s by a team of Czechoslovak gun designers led by Jiří Čermák. It was a modular small arms system, intended for export and built around a common receiver. It was chambered for 7.62 x 51 NATO ammunition. It is believed that URZ achieved virtually no sales at all, and apparently, never went into mass production, despite marketing attempts that lasted until the mid-1970s.

The URZ rifle used an interesting delayed blowback action, somewhat similar in its basic idea to the Vorgrimler roller delayed system (such as used in various HK weapons like G3 or MP5), having a two-part bolt with a couple of rollers on the head. However, instead of being pressed out of recesses in the receiver and against the bolt body, in this system rollers were used to rotate the bolt head while riding on inclined surfaces on the bolt carrier body and the barrel extension, thus slowing down the bolt head movement during the initial stages of opening. The “Plamen” system was available in 4 basic configurations – Automatic Rifle (AR), Light Machinegun (LM), Heavy Machinegun (HM) and Tank Weapon (TW).

In AR, LM and HM configurations, the gun fired single shots from a closed bolt and full auto from an open bolt. In TW configuration it fired only in fully automatic and from an open bolt. In all configurations except HM the URZ was fed using special belt feed “magazines” (drum-shaped containers) with built-in belt feed sprockets and empty link collectors. A special low-capacity magazine was designed for launching blank grenade rounds. Each belt magazine contained 50 rounds of linked ammunition. In the Heavy Machinegun configuration the URZ used standard 250 round belts and a special feed unit instead of the belt “magazine”. This version of the rifle was fitted with a wooden shoulder stock with rubber buttpad, and a short wooden forend. Barrels were fitted with flash hiders that also served as launcher spigots for rifle grenades.

Data for rifle configuration