Underwater Firearm Prototypes

[World B4]

The AG-026 was a prototype underwater machine gun developed for use in the Triton-1M midget sub
https://guns.fandom.com/wiki/AG-026
The B-VI-07 was a prototype that was a precursor design to the SPP-1
https://guns.fandom.com/wiki/B-VI-307
VBR OWP is a modern Belgian prototype underwater pistol
https://guns.fandom.com/wiki/VBR_OWP
The Shkval is an AK-74 deriver underwater assault rifle prototype. Not much about it is known.
https://guns.fandom.com/wiki/Shkval
In the incredible article by H I Sutton on existing underwater firearms, he includes a section on the Self Supressed Unit, a project in Yugoslavia for an underwater pistol that was cancelled due to the breakup of the nation. Development wan't entirely halted, but the intended customer was gone so it never entered service.
http://www.hisutton.com/Covert_Shores_Guide_to_Underwater_weapons.html

 

[Jemiba]

Already mentioned by Covert Shores, nevertheless, here are the entries of some underwater guns from the
"Mitteilungen des Vereins der Freunde und Förderer der Wehrtechnischen Studiensammlung e.V. ", issue 13, 1996,
when the following weapons could be added to the collection of this association.

- Heckler & Koch, Germany : P-11
- Institute of Precise Mechanical Engineering, Izhevsk, Soviet Union, 1971 : Underwater Assault Rifle APS
- Tznitochmash Klimovsk, Soviet Union, 1971 : SPP-1

 

[Bottleship]

Other Soviet belt-fed machine gun, theme "Moruzh" ("Morskoye ORUZHie" - "Naval Weapon"):

...
Theme "Medusa" - large-caliber machine guns, 13.1/8 mm and 14.95/8 mm cartridges (KEP shells).
13.1/8 mm - penetrate a 10 mm steel plate at 23 m (underwater)
14.95/8 mm - 600 mps (underwater)
Project with 14.95/8 mm cartridge - 120 rpm, 60-round and more in belt.
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Modern Russian project - 12 gauge 3 inch case cartridge with special bullet, for using at air and underwater.
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Modern Russian 5.45x39 PSP - underwater bullet:


Bullets:
Standart - 16 g (246 gr), 333 mps (1092 fps) (air)
Trainig - 8 g (123 gr), 430 mps (1711 fps) (air)
5.45x39 PSP more effective in water and at air, than old 4.5 and 5.66 mm cartridges. Also, weapon for this cartridge can use standart military 5.45x39.
Analogical cartridge created based on 7.62x39.
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Experimental "Bars-1", or also ADSh (Avtomat Dvuhsredniy Shturmovoy - AR double-environment assault) - 7.62x39, based on AKM. Author - Alexander Shevchenko, Russian gunmaker (not Victor Shevchenko, Ukrainian gunmaker). Damped automatic, very accuracy at air, in full-auto 3x20 firing, with new compensator, better than AKM 9.44 times, than M16A1 7.77 times, than M16A2 2.91 times, than AK-74M 3 times.

 

[drejr]

 

[Bottleship]

Also, Bars-1:

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Early soviet underwater cartridge in 7.62x39 case (not use in Bars-1):


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In Russia projected new double-environment 4.6x30 cartridge (it's not HK 4.6x30 variant) with bullets for water and air, and projected new special pistol in this cartridge.
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Data about "Shkval" - weight (without cartridges) 3.05 kg, lenght 610/780 mm, barrel lenght 415 mm, distance of fire - 1000 metres at air and 10 metres at water (depth 5 metres), rate of fire - 800/1800 rpm.
(data from Guns.ru - Russian forum with journalists, gunmakers, military historicists, and also hunters and sportsmans)
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Alexander Shevchenko with unknown 5.45 mm project: