Soviet AG-026 Prototype Underwater Machine Gun

    Soviet AG-026 Prototype Underwater Machinegun (1973)

    AG-026 (АГ-026) underwater machine gun was developed by TsNII TochMash along with other Soviet amphibious weapons such as the APS (АПС) assault rifle and SPP-1 (СПП-1) pistol. Although all of these guns are rare firearms, the pistol and rifle are relatively more common and better known as they were adopted by the Soviet military. The AG-026 machine gun was never adopted and has always been a mystery with very scarce information and a few pictures available. During the ARMY-2020 exhibition, TsNII TochMash for the first time ever displayed this gun among other rare and prototype weapons they have developed over the years. Additionally, they released the following short video showing this unicorn firearm.

    AG-026 was developed in 1973 within an R&D program called Moruzh-2 (Моруж‑2). The head designer of this weapon is Pyotr Tkachev. This machine gun was designed to be used in the Triton series of Soviet mini-submarines/frogmen transporting vehicles. The lug under the barrel is for mounting the gun to the mentioned vehicles. Reportedly, there was also a front grip that could be attached to the lug for using the gun offhand.

    Soviet AG-026 Prototype Underwater Machinegun (1985)

    AG-026 is a simple/direct blowback firearm firing from an open bolt with a fixed firing pin. The bolt itself is fairly compact and low profile with a small cross-sectional area for decreased resistance while cycling in water, however, it is linked to а pair of rotating gears/flywheels enclosed in the circular housings mounted to either side of the breech area. The gears increase the reciprocating mass to make the blowback action work properly. The gun was charged by rotating the handles located on the circular gear housings.

    Soviet AG-026 Prototype Underwater Machinegun (1978)

    The AG-026 machine gun is chambered in 5.66x39mm, the same cartridge used in the APS rifle. This cartridge is based on the 5.45x39mm case, has a long 120mm (4.7″) projectile designed for stabilizing underwater, enhanced primer and neck seal as well as anti-corrosive coating on the case and bullet. The main load of 5.66x39mm cartridge is called MPS (МПС). Its 20 gram (308 grains) projectile has a muzzle velocity of 365 m/s (1200 fps). The effective range of this bullet fired from AG-026 is 30 meters at a 5-meter submersion depth, 10 meters at a 40-meter depth and up to 100 meters in the air.


    5.66x39mm cartridge, MPS load. Photo credit:

    The AG-026 machine gun was fed from a 27-round rotary magazine that represents a rotating closed-chain ammunition belt placed into an outer protective shell. The gun has a push feed action where the bolt simply pushes the aligned cartridge from the link to the chamber. The only control is apparently the safety selector on the right side of the receiver with safe and full-auto modes. The overall weight of this machine gun is 4.85 kilograms (10.7 lbs) and it has the following dimensions: length – 585mm (23″), width – 135mm (5.3″), height – 243mm (9.6″).

    Soviet AG-026 Prototype Underwater Machinegun (1984)

    Below you can find a couple of other short videos published by TsNII TochMash showing the APS rifle and SPP-1 pistol.

    Images by TsNII TochMash,

    Hrachya H

    Managing Editor

    Being a lifelong firearms enthusiast, Hrachya always enjoys studying the history and design of guns and ammunition. He also writes for and
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