Frogman with a Russian IDA71 rebreather, riding a Protei 5, carrying an APS Russian underwater rifle

The APS Underwater Assault Rifle (5.56 mm) is a derivative of the AK47, designed and made in Russia in the early 1970's for use underwater by frogmen. Underwater, ordinary-shaped bullets are inaccurate and very short-range. As a result, this rifle fires a steel bolt 120 mm (4.75 in) long. Its magazine holds 26 cartridges. This is a CGI image of a frogman using the Russian kit as listed here and described at these links. ... This is a CGI image of a frogman using the Russian kit as listed here and described at these links. ... 3 views of a frogman with IDA rebreather The Russian IDA71 military and naval rebreather is an oxygen rebreather intended for use by naval and military divers. ... Inspiration Closed Circuit Diving Rebreather Description A rebreather is a type of breathing equipment that provides a breathing gas containing oxygen and recycles exhaled gas. ... Frogman with a Russian IDA71 rebreather, riding a Protei 5, carrying an APS Russian underwater rifle The Protei-5 is a small Russian one-man diver-carrying vehicle intended for use by commando frogmen such as those in the Spetsnaz. ... The AK-47 (for Avtomat Kalashnikova model 1947 goda, Russian: автомат Калашникова образца 1947 года) is an assault rifle designed in 1947 by Mikhail Kalashnikov, produced by Russian arms manufacturer IZH, and used in many Eastern bloc nations during the Cold War. ... The Russian Federation (Russian: Росси́йская Федера́ция, transliteration: Rossiyskaya Federatsiya or Rossijskaja Federacija), or Russia (Russian: Росси́я, transliteration: Rossiya or Rossija), is a country that stretches over a vast expanse of eastern Europe and northern Asia. ... For the Wizard of Oz series character, see Frogman (Oz character). ...

'APS' stands for 'Avtomat Podvodnyy Spetsialnyy' = "Special Underwater Automatic rifle".

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. Its range decreases with increasing depth, presumably due to increasing backward suction caused by cavitation behind the projectile. Rifling is the means by which a firearm gyroscopically stabilizes a projectile. ... Hydrodynamics is fluid dynamics applied to liquids, such as water, alcohol, oil, and blood. ... Cavitation is the phenomenon where small cavities of partial vacuum form in fluid, then rapidly collapse, producing a sharp sound. ...

The APS is longer range and has more penetrating power than spearguns. This is useful in such situations as shooting through reinforced drysuits, and protective (not air-holding) helmets, and thick tough parts of breathing sets and their harnesses, and plastic casings and transparent covers of some small underwater vehicles. Spearfishing is a form of fishing that has been popular the whole world over for centuries. ... Two divers, one wearing a 1 atmosphere diving suit and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935. ...

See also

• Russian SPP-1 Underwater Pistol
• Heckler & Koch P11 Underwater Pistol

The 4. ... The HK P11 is a special-purpose Heckler und Koch pistol designed to be used underwater, where ordinary-shaped bullets are inaccurate and have very short range. ...

External links

• Picture and information (http://world.guns.ru/assault/as69-e.htm)
• Rosoboronexport's web site (http://www.roe.ru/main.htm) (and on that page, left-click "Skip intro", then "Export products", then "Special forces").

As far as is known, no USA copy of the APS has been made in the real world.