The Vollmer M 35 (also known as Vollmer-Maschinenkarabiner or MKb 35) consisted of a series of experimental automatic rifles developed by Heinrich Vollmer in the 1930s. The Vollmer rifles were chambered in an intermediate cartridge that was co-developed with Gustav Genschow and Co. (GECO) starting in 1934, under a Heereswaffenamt contract.[1][2]
The M 35 was a gas-operated design, reminiscent of an earlier semi-automatic design of Vollmer—the 7.92×57mm Selbstladegewehr 29 (SG 29). Trials with Vollmer's Maschinenkarabine were conducted as early as 1935 at Biberach and later at Kummersdorf. The early version had a 20-round detachable box magazine and could fire at a rate of about 1,000 rpm. Development continued with the improved versions M 35A, M 35/II (1937) and M 35/III through 1938. The later versions had intentionally reduced rate of fire to only about 300–400rpm.[3] It weighed about 9.5 pounds (4.3 kg) and was about 38 inches (97 cm) long. About 25 prototypes were manufactured for testing.[1] The gun was apparently very expensive to manufacture, costing 4000 Reichsmarks,[2] although this was the unit cost for the prototype series.[4]
The cartridge developed also had several variants including 7.75×40.5 mm, 7.75×39.5mm, and possibly a 7.62mm version as well, and had a total length of approximately 55 mm. (The actual calibre was apparently 7.9mm, with a bullet 8.05mm in diameter.[5]) Muzzle velocity was about 700 m/s (2,280 feet per second). The boat-tailed bullet weighted 140 grains (9 grams).[6]
Ultimately, Nazi Germany would adopt a different intermediate cartridge and service assault rifle: the MKB 42 series leading to the Sturmgewehr 44. The later Soviet 7.62×39mm M43 cartridge bore more dimensional similarity to the GECO M 35 cartridge than it did to the German 7.92×33mm Kurz that was used in the Sturmgewehr.[1][2]