The Gewehr 43 or Karabiner 43 (abbreviated G43, K43, Gew 43, Kar 43) is a 7.92×57mm Mauser caliber semi-automatic rifle developed by Germany during World War II.

The problems with both designs stemmed from a demand made by the Army that the rifles would not use holes drilled into the barrel, known as gas ports, to run the automatic loading mechanism.

Meeting this requirement meant the designs had to use uncommon mechanisms that were simply unreliable and highly prone to fouling.

The German invasion of the Soviet Union led to small numbers of the SVT-40 being captured and returned to Germany for examination.

These used a simple gas mechanism powered from a port cut into the barrel about 1/3 of the way back from the end and replaced the conventional stripper reloads with a modern box magazine.

Just prior to the opening of hostilities the Soviet Red Army had started re-arming its infantry, complementing its older bolt-action rifles with the new semi-automatic SVT-38s and SVT-40s.

The simpler, sturdier design and mechanism of the G43 made it lighter, easier to produce, more reliable, and also much tougher than the Gewehr 41; German mountain troops would use them as ladder rungs during climbing.

[2] The total production by the end of the war is estimated to have been 402,713 of both models, including at least 53,435 sniper rifles: these G43/K43s were used as designated marksman/sniper weapons, fitted with the Zielfernrohr 43 (ZF 43/ZF 4) telescopic sight with 4× magnification.

Variations in barrel length did exist, but those were the product of machining tolerances, differences between factories, and/or experimental long-barreled rifles.

[3] Though most G43/K43s are equipped with a telescopic sight mounting rail, the vast majority of the rifles were issued in their standard infantry form without a scope.

[6] The original gas system of the Gewehr 43 is copiously gassed and was designed for using World War II German service ammunition in the presence of heavy fouling or icing.

conform 7.92×57mm Mauser) ammunition can move the gas piston overly fast and hard against the bolt carrier which in turn hits the receiver harder.

Especially on late war Gewehr 43's the steel quality of the sheet metal rear of the receiver could be poor and the heat treatment of the bolt carrier could be suboptimal.