The most difficult pistols riddles

The MP 40 designed in 1938 by Heinrich Vollmer Its advanced and modern features made it a favorite among soldiers and popular in countries from various parts of the world after the war. It was often erroneously called "Schmeisser" by the Allies, despite Hugo Schmeisser's non-involvement in the weapon's design and production.

Samuel Colt missed a great opportunity in firearms development when he dismissed an idea from one of his gunsmiths, Rollin White. White proposed a "bored-through" revolver cylinder to allow the use of metallic cartridges in a handgun. After Colt fired White for suggesting an improvement to his revolver, White took his idea to Colt's competitor, Smith & Wesson, who patented his invention and kept Colt from being able to build cartridge firearms for almost 20 years.

Helical magazines extend the drum magazine design so that rounds follow a spiral path around an auger-shaped rotating follower or drive member, allowing for large ammunition capacity in a magazine that can be adapted to increase ammo capacity with only a minor increase to the dimensions of an unloaded gun. This type of magazine is used by the Calico M960, Bizon SMG, Long Wind CS/LS06 and KBP PP90M1.

The Uzi is a family of Israeli open-bolt, blowback-operated submachine guns. Smaller variants are considered to be machine pistols. The Uzi was one of the first weapons to use a telescoping bolt design which allows the magazine to be housed in the pistol grip for a shorter weapon.

The MP 40 (Maschinenpistole 40) was a submachine gun chambered for the 9×19mm Parabellum cartridge. It was developed in Nazi Germany and used extensively by the Axis powers during the Second World War.