The Vollmer M35 automatic carbine was the creation of one Heinrich Vollmer, and it ran along the lines of an earlier Vollmer self-loading design, the 7.92×57mm Selbstladegewehr 29 (SG 29), a design earlier rejected by the Heereswaffenamt. At this time, the German ordnance authorities were still somewhat suspicious – for no sound reason – of gas-operated weapons that tapped propellant gas directly off the barrel. Vollmer’s gun used a different form of gas mechanism, similar to the Bang system described earlier, with a gas-powered muzzle nozzle unlocking the bolt and pushing it through its recoil phase.
There seems to have been considerable promise in the Vollmer system. During early firing trials at Biberach in June 1935, it demonstrated the ability to eat through the contents of 20-round detachable box magazines at a rate of 1,000rpm, although the high ammunition consumption did not endear it to the authorities. Revised and improved models were produced later in the year, curing feed and ejection problems. In its A35/II version, the Vollmer rifle gave impressive performance during further trials in 1937, especially in terms of its reliability. Following rate-of-fire reductions to 300–400rpm, by early 1938 the Heereswaffenamt seemed to be considering adopting the rifle as an official weapon of the Heer. Testing continued to produce glowing results with the updated A35/II, but then in August 1938 the interest from the Heereswaffenamt stopped dead, with little explanation.
The Vollmer was essentially history’s first automatic rifle to fire an intermediate cartridge, and why development ceased is puzzling. Automatic rifles are certainly more complicated and expensive to produce than bolt-action counterparts, and war-production considerations might have been foremost in the minds of the Heereswaffenamt. However, the former director of Geco, H.G. Winter, after the war gave his thoughts on the reason:
The weapons developed by Vollmer in the years 1935–39 were excellent, and were especially attractive through their reliability, as was the ammunition. However, the responsible military departments at the time, by and large, did not recognize the uniqueness of this new type of weapon and ammunition, to have encouraged and recommended its further development by all means possible. Only General Kittel, who at that time still only held the rank of Major, had realized its importance. (Quoted in Senich 1987: 49)
From one perspective, Winter’s explanation certainly seems plausible. The combination of bolt-action rifle, submachine gun and machine gun that armed the Heer probably didn’t seem to have pressing problems when it came to killing people on the battlefield. Furthermore, the Germans had not yet encountered the combat advantages possessed by an opponent armed with a semi-automatic rifle; fighting against the Soviets from 1941 and the Americans from 1942 would remove this veil from German eyes.