G-3

The development of the G3 began in the 1950s through a partnership between Heckler & Koch and the Spanish state-owned manufacturer CETME. The design lineage traces back to the Mauser Abteilung 37 and the Gerät 06H prototype from the final years of World War II. Following the war, German technicians relocated to France to work at the Centre d'Etudes et d'Armement de Mulhouse, where the StG 45(M) mechanism was modified. Development continued in Spain as the CETME Modelo 2. After the West German Bundesgrenzschutz and Bundeswehr expressed interest in a variant chambered for standard NATO ammunition, Heckler & Koch implemented technical refinements to the CETME design. The West German government officially adopted the resulting weapon in January 1959.

The G3 is a selective-fire automatic weapon employing a roller-delayed blowback operating system. The two-piece bolt assembly uses two cylindrical rollers to engage locking recesses in the barrel extension, delaying the breech opening until internal pressure drops to safe levels. To assist extraction, the chamber is manufactured with longitudinal gas relief flutes that allow propellant gases to equalize pressure around the cartridge case. The receiver is constructed from stamped and pressed sheet steel components joined by spot welding. Its modular design allows for the interchange of buttstocks, handguards, and trigger groups through the removal of simple push-pins. Aiming is accomplished via a hooded front post and a rotary diopter rear drum.

Entering service in 1959, the G3 functioned as the primary infantry rifle for the West German Bundeswehr until the adoption of the G36. The weapon was exported to more than 70 countries, and license production was established in nations including Pakistan, Portugal, Sweden, Norway, and Iran. Variants include the G3A3, featuring a fixed polymer stock and free-floating barrel, and the G3A4, which utilizes a retractable metal stock. The rifle's architecture provided the foundation for a family of firearms including the MP5 submachine gun and the PSG1 precision rifle. Specialized models include the G3SG/1 sharpshooter rifle and the G3K carbine. Modernized versions remain in use with reserve units and international law enforcement agencies.