Soviet underwater rifle being fired

Did he pick up the empty brass ;-)

A couple of interesting things about this rifle; one, it’s gas-operated, which makes me wonder how they got it to function reliably both in the water and in the air, and two, they even make a tracer round for this rifle. The rifle is smooth-bored, and depends on the bubble of cavitation behind the dart to keep it stabilized, and is supposed to have a lethal range of up to 30 metres at a depth of 5 metres.

To my knowledge this is Chinese photo and possible this is not Russian frogman.

I was about to post cartridge photos (I love special purpose stuff)…and realized there must be several former posts/threads…and there is

SO…type “under water” in the search bar…and there is plenty written and photo’ed about the SPP & APS rounds…no sense in me retyping well posted and discussed threads


As Yuri said, this gun is not to be fired in the open air, except in emergency circumstances, and in this case, useful range was less than some meters, with almost no precision.

It seems that more recently appeared the APS-DT, with a rifled barrel, and a sliding contraption, with a lug, under the receiver, allowing to accept a either the “king-size” magazine, or a smaller one with ordinary 5,45x39 M74 cartridges. So it would be theoretically possible to use the gun either underwater, or in the air by a very simple manipulation and a change of magazine.

The underwater round was designed by Ivan KASYUNOV, after many trials and experimental configurations had been tried.
An underwater tracer round is no way a problem, a tracing mixture, if dry and welll sealed being able to burn correctly underwater.

As Yuri said, the conception of the long flechette is quite interesting, its behaviour being due to cavitation phenomens generated by the flat tip, the “bullet” makes its translation in an actual air “bubble” avoiding any contact with the water outside

About the fact that the gun is gas operated, this is not a problem either, as the power of gases produced at firing is more than sufficient to expell any water from the gas ports or channels.

By the way, even if the weapon was first disclosed in 1993, it had been conceived and built well sooner, from 1969, at Klimovsk.

In 1989, when George Bush (Sr) and Mikhail Gorbatchev met in Malta Island, 16 frogmen from the Russian Navy Special Forces were diving around the warships with APS guns to assume their safety. They had been given order to shoot immediately any person approaching the vessels under a 200 m limit…


Yet, Bolotin’s “History of Soviet Small Arms & Ammunition” says that the rifle was designed to “operate reliably in both the water and the air”. There’s no doubt that it’s not nearly as EFFECTIVE in the air, since the darts are fired through a smooth-bore barrel, but he even gives an “effective range” of 30 metres in the air. As an aside, are there any references which explain the acronyms for the ammunition, MPS and MPST? None of the references I can find (Bolotin, Monetchikov, or others) explain what the “M” stands for.

Here is a earlier post I started about Russian underwater ammunition that may be of interest here? I was blown away learning about these bullets and weapons. Crazy, but so cool!

Jason … underwater

[quote=“APFSDS”]Here is a earlier post I started about Russian underwater ammunition that may be of interest here? I was blown away learning about these bullets and weapons. Crazy, but so cool!

Jason … underwater[/quote]

Jason then you certainly would love the 105mm APFSDS for shooting into the water at water targets.

No way, do they really make one of those EOD? I think I am starting to drool a little :-)


Jason here it is, note the tip shape:

I like very much to get this cartridges for my colecction

WOW, too cool! The blunt tip design is definitly something I have not seen before. I have so many questions about this projectile.

  • What gun shoots this?
  • What Country makes it?
  • Is thier a Type Classification?
  • What kind of case does it use?
  • Dying to see a photograph of the complete round.



Jason, this is only abstract (USH1938H) from US patent US5955698:
A supercavitating water-entry projectile having empennage on the aft end which provides both aerodynamic and hydrodynamic stability and a supercavitating nose section is provided. A representative projectile is a subcaliber munition adapted for use in a 25 mm weapon using a sabot currently in use with the M919 round. The projectile has circumferential grooves around its center section to match these sabots. A key feature in the invention is the size and shape of the nose section. The projectile has a novel high strength extended blunt nose section followed by a truncated conical section which angles towards the body of the projectile in the range of five degrees. During underwater trajectory, the entire projectile is contained within the cavitation bubble formed by the blunt nose tip. The projectile’s aft empennage, which provides both aerodynamic and hydrodynamic stability, fits within the bore of the weapon.

You can check full patent here: … projectile

Thank you so much Yuri! Beyond fascinating and so cleaver! I love how they use cavitation as a means of creating a air bubble around the projectile underwater. When it comes to killing, man is so dam smart! The opposable thumb always amazes me :-)

Besides a torpedo, a spear-gun, or that cool Russian underwater missile, this is probably the largest underwater projectile or at least one that transitions from air into water which is pretty difficult to achieve penetration and a quality trajectory I would think?

Kinda reminds of of a US TV show called “Myth Busters”. IN one episode they wanted to test the movie myth on how deadly different projectiles were at killing when shot from land into the water. I was so surprised that the smaller 9MM shot from a pistol was deadly at a much deeper depth ( I think 7 feet?) then a high power rifle. They even shot a 50-Cal from a Barrett and like the other high power rifle rounds, their projectiles turned to dust after a few inches of hitting the water. I wonder if the bullets had blunt tips if they would cause a cavitation bubble and have better underwater penetration?



DAAAAAUUUUUMMMMM! Just read the patent stuff Yuri posted. UNBELIEVABLE!!!

You’re gonna have to get you one of those Jason. Your personal HOLY GRAIL

Yeah, I think the hunt is on! :-) I’ll need to get a extra one for Pepper’s “Special Purpose Ammunition” collection as this is pretty freaking special!!! WOW!

Uh THREE?!?!

WOOPS! I’ll be sure to get a dozen or so extra to share, haha!

Hi, Jason!
Cavitation is not simple effect