SPP-1 underwater pistol
The SPP-1 underwater pistol was made in the Soviet Union for use by Soviet frogmen as an underwater firearm. It was developed in the late 1960s and accepted for use in 1975. Under water, ordinary-shaped bullets are inaccurate and very short-range. As a result, this pistol fires a round-based caliber steel dart about long, weighing , which has longer range and more penetrating power than speargun spears. The complete cartridge is long and weighs . Design. The SPP-1 has four barrels, each containing one cartridge. Its ammunition comes as a magazine of four cartridges which is  inserted into the pistol's breech. Its barrel is not rifled; the fired projectile is kept in line by hydrodynamic effects. As a result, it is somewhat inaccurate when fired out of water. A double-action firing mechanism fires one cartridge sequentially for each pull of the trigger. When all four cartridges are spent, the gun can be reloaded above or below water. The SPP-1M pistol is essentially the same as the SPP-1, with the following differences: The weapon was designed by Vladimir Simonov, the cartridge by Pyotr Sazonov and Oleg Kravchenko. Simonov also designed the APS amphibious rifle . Performance. Depth reduces range because the higher pressure closes the cavity sooner. Once the projectile is no longer supercavitating, hydrodynamic drag increases greatly, and the projectile becomes unstable. Lethal range is defined as the range from which it can easily penetrate a padded underwater suit or a thick glass faceplate. It is manufactured by TOZ (Tulsky Oruzheiny Zavod/ Тульский Оружейный Завод) Tula Arms Plant, and exported by Rosoboronexport, the state agency for Russia's export and import of defense-related products. Variants. The SPP-1M has been copied by Iran.