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The Frommer Stop is a semi-automatic pistol produced in 1912 by FÉG of Hungary. It was used throughout World War I and World War II by the Hungarian Armed Forces. Designer Rudolf Frommer adapted the design from another pistol that fired .32 ACP (7.65mm) from a seven-round detachable magazine. The weapon is unusual among automatic pistols in using a long-recoil system of operation. The Frommer Stop was available in 2 proprietary cartridges, similar to the .32 and .380 ACP, respectively. However, the Stop's cartridges had more powder and fired a heavier bullet. The Stop could fire regular .32 and .380 rounds, though, with less reliability. 
The Frommer Stop has a very high rate of fire and respectable damage, as well as relatively low recoil. This makes it a very good weapon for rapidly taking down lone enemies. However, its magazine capacity makes it difficult to engage multiple enemies. This is somewhat countered by the extremely short reload time.
The Frommer Stop Auto is a carbine form of the normal pistol. It was first seen in the Battlefield 1 Gameplay Series: Vehicles video as a customization option.
The Frommer Stop Auto fills a similar role to the G18 from previous battlefield installments. It is an extremely fast firing, pistol-like weapon that is forced to reload often but is deadly efficient at taking down lone enemies. The rate of fire for the Auto is verging on uncontrollable, so one should play with it like they do when using the Automatico M1918 - firing from the hip at close range and reloading often. The Frommer Stop Auto is definitely a good choice for Pilots and Tankers on more closed maps like Suez and Amiens, but is less useful in the wide-open spaces of Sinai Desert and Monte Grappa.