Concept
The 7.92×33mm Kurz (designated as the 7.92 x 33 kurz by the C.I.P.) is a rimless bottlenecked intermediate rifle cartridge developed in Nazi Germany prior to and during World War II, specifically intended for development of the Sturmgewehr 44 (assault rifle). The ammunition is also referred to as 7.9mm Kurz (Kurz meaning "short"), 7.9 Kurz, 7.9mmK, or 8×33 Polte. The round was developed as a compromise between the longer 7.92×57mm full-power rifle cartridge and the 9×19mm Parabellum pistol cartridge, and is the first mass-used intermediate cartridge (Mittelpatrone) in the world. The 7.92×33mm Kurz has a 2.22 ml (34.3 grain H2O) cartridge case capacity. 7.92×33mm Kurz maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 17.5 degrees. The common rifling twist rate for this cartridge is 240 mm (1 in 9.45 in), four grooves, Ø lands = , Ø grooves = , land width = and the primer type is Berdan or boxer (in large rifle size). According to the official Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P.) rulings, the 7.92×33mm Kurz can handle up to Pmax piezo pressure. In C.I.P. regulated countries every rifle-cartridge combination has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that 7.92×33mm Kurz chambered arms in C.I.P. regulated countries were, as of 2014, proof tested at PE piezo pressure. In German military instructions, the caliber was often deemed unimportant; the name was emphasized. The 7.92×33mm Kurz was referred to as the Pistolenpatrone M43 (pistol cartridge model 1943) or Pistolen-Munition M43 (pistol ammunition model 1943). This was part of the same duplicity under which the StG44 was originally designated as a "machine pistol" to disguise the true nature of the weapon from Hitler. After the eventual approval and acceptance of the Sturmgewehr 44, it was redesignated as the "short cartridge model 1943" (Kurzpatrone 43).
