High Quality Content by WIKIPEDIA articles! The APS Underwater Assault Rifle or Special Underwater Automatic is an AK-47 derivative designed by the Soviet Union in the early 1970s as an underwater firearm. It was adopted in 1975. It is made by the Tula Arms Plant in Russia. It is exported by Rosoboroneksport.Underwater, ordinary-shaped bullets are inaccurate and very short-range. As a result, this rifle fires a steel bolt caliber 5.66 mm and 120 mm 4.75 in long. Its magazine holds 26 cartridges. The APS's barrel is not rifled; the fired projectile is kept in line by hydrodynamic effects. As a result, the APS is somewhat inaccurate when fired out of water.The APS has a longer range and more penetrating power than spearguns. This is useful in such situations as shooting through reinforced dry suits, and protective helmets whether air-holding or not, thick tough parts of breathing sets and their harnesses, and plastic casings and transparent covers of some small underwater vehicles.The APS is more powerful than a pistol, but is bulkier and takes longer to aim, particularly swinging its long barrel and big flat magazine sideways through water.