Bergmann MP 18

Issued to Stormtrooper squads in the final months of WWI, the MP 18 was designed to sweep enemy trenches of defenders too closely packed for a bolt-action rifle to effectively engage. The Allies considered the weapon so uniquely dangerous that the 1919 Treaty of Versailles explicitly banned Germany from producing or possessing submachine guns, permitting only 1,134 for police use - the first and only time in history a single weapon class was outlawed by international treaty. Bergmann and Schmeisser kept the design alive through secret production and foreign licensing, ensuring that the submachine gun concept survived to dominate the infantry battlefields of the 20th century.

The TM 08 snail drum magazine was mechanically unreliable and required a special loader tool to fill; later MP 18,I conversions (per Weimar-era police contracts) replaced it with a 20- or 30-round straight box magazine inserted through a modified left-side magazine well. The MP 18 entered service in limited numbers during the German Spring Offensive of 1918 and was issued to specialized Stormtrooper units at a scale of approximately one per squad. Although the Treaty of Versailles restricted German submachine gun holdings to 1,134 weapons for police use, Bergmann continued covert production into 1920, and many weapons were sold or smuggled abroad. The design's DNA is present in the Schmeisser MP 28, Lanchester, Sten, and by extension most pistol-caliber automatic weapons of the 20th century. Chinese arsenals at Tsingtao (Qingdao) and Dagu produced domestic copies chambered in both 9x19mm and 7.63x25mm Mauser. Muzzle energy is approximate based on standard 9x19mm service ammunition at 380 m/s.