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.
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.
[3] It weighed about 9.5 pounds (4.3 kg) and was about 38 inches (97 cm) long.
[6] Ultimately, Nazi Germany would adopt a different intermediate cartridge and service assault rifle: the MKB 42 series leading to the Sturmgewehr 44.