1948, which differed only from the German rifle in that it had the shorter bolt-action of the Model 1924 series of Mauser rifles. In addition, in 1943, the Spaniards were manufacturing a slightly modified version, but with a straight bolt handle. Gewehr 41 By 1940, it became apparent that some form of a semi-automatic rifle, with a higher rate of fire than existing bolt-action models, was necessary to improve the infantry's combat efficiency. The Wehrmacht issued a specification to various manufacturers, and both Mauser and Walther submitted prototypes that were very similar. The Mauser design, the G41(M), failed. Only 6,673 were produced before production was halted, and of these, 1,673 were returned as unusable. The Walther design, the G41(W), is in outward appearance not unlike the Gewehr 43 (see below). Most metal parts on this rifle were machined steel, and some rifles, especially later examples utilized bakelite type plastic handguards. The Walther design was more successful because the designers had simply neglected the last two restrictions listed in the main article. These rifles, along with their G41(M) counterparts, suffered from gas system fouling defects. These problems seemed to stem from the overly complex muzzle trap system becoming excessively corroded from the use of corrosive salts in the ammunition primers, and carbon fouling. The muzzle assembly consisted of many fine parts and was difficult to disassemble, keep clean, and maintain in field conditions. G41(W) rifles were produced at two factories, namely Walther at Zella Mehlis and Berlin-Lübecker. Varying sources put production figures between 40,000 and 145,000 units. These rifles saw a high attrition rate on the Eastern front. Gewehr 43 In 1941, Nazi Germany invaded the Soviet Union as part of Operation Barbarossa. Just prior to the opening of hostilities, the Red Army had started re-arming its infantry, replacing its older bolt-action rifles with the new semi-automatic Tokarev SVT38s and SVT40s. This proved to be something of a shock to the Germans, who ramped up their semi-automatic rifle development efforts significantly. The Tokarev used a simple gas-operated mechanism, which was soon emulated by Walther, thus producing the Gewehr 43 (or 'G43') from the handicapped G41. The simpler mechanism of the G43 made it lighter, easier to mass-produce, and far more reliable. The addition of a 10-round detachable box magazine also solved the slow reloading problem. The Gewehr 43 was put into production in October 1943, and followed in 1944 by the