HK P11: NATO’s Secret Underwater Pistol

0:00 Introduction and History of Underwater Firearms
0:55 Engineering Challenges and Russian Underwater Firearms
2:07 Development, Adoption, and Global Usage of the H&K P11
3:36 Examination of H&K P11: Fired Barrel Cluster and Firing Mechanics
5:24 Unique Features of the H&K P 11: Silence and Sealed Sabot System
7:45 The Electrical System and Battery Compartment of the HK P 11
8:42 Web Gear and Standard Load Out for the H&K P11
9:24 The Secrecy Surrounding the H&K P11
10:16 Conclusion and Acknowledgements

Developed by Heckler & Kock and adopted by the German army in 1976, the P11 has become the de facto underwater pistol for all NATO militaries. It is an electrically-fired pepperbox style pistol with five barrels. Each barrel is preloaded and the barrel clusters are easily swapped – and must be returned to H&K for reloading. Two different types of ammunition are made; DM91 bullets for firing in air and DM101 flechette darts for firing underwater.

Many thanks to Andy at H&K for inspiring me to do this video, and to the British Royal Armouries for giving me access to this P11 to film!


  1. “(…)P11(…)”
    Relevant patent is US7987624B1 Flashless electric firearm and ammunition therefor
    Note that wording suggests main reason to design this weapon was need for noiseless and ability to utilize the firearm of the invention even immediately after it has been submerged in water is mentioned in passing.
    P11 appeared (under fake name and non-lethal) in Nightfire video game of James Bond franchise

  2. An excellent video – so much more information than most sources give. I love the solid clicks on locking and unlocking the barrel cluster. The tight-lipped secrecy thing no doubt increased HK’s mystique.

  3. Why not incorporate fresh batteries sealed inside each barrel cluster?
    Or do batteries have a shorter shelf-life radius Han gunpowder?

    • Yes they have. While gun powder can last for many decades, normal alkaline batteries have a self-discharge of ~5% of their maximum energy content per year. That means that the battery is dead after ~20 years even if it is not used. But it is possible that the pistol requires a battery with a least 50%, for example, of it’s initial capacity to shoot 3 or 4 barrel clusters reliably.

  4. Did I miss something, but does the absence of Ian’s usual references to a weapon’s markings and serial numbers mean there was neither?

    • No markings are visible in the video except the open/closed markings on the bottom of the batterypack . They may have asked Ian not to show any markings and skip that subject while filming . . . And did you notice the blue gloves ? Could it be , that Ian was not allowed to touch the gun with his bare hands ? I am pretty sure , that a polymer gun would not be harmed by skin contact . . .
      The room also looked strangely empty – leaving the viewer perfectly clueless regarding the location ^^ .

    • There is a marking and serial number on the left side of the grip . It is visible @ 4:33 and it says : P11 and 1001 ! 🙂

  5. A studio-built copy of this powered by compressed air showed up in the movie Tomb Raider; The Cradle of Life (2003) in Lara Croft’s (Angelina Jolie) hands.

    This version seems to be the one most people have seen, due to showing up in games since that time.

    The U.S. Navy’s SEAL teams have over the years used Glock 17s in 9 x 19mm with special “underwater” firing pins. These have flutes machined in to allow water to flow around the firing pin/striker as it snaps forward to indent the primer, thus preventing a “light hit” due to the functional incompressibility of water.

    The SEALs have also used M1911A1s in .45 ACP. They can be fired quite normally underwater, as can single and double-action revolvers in most calibers. I would assume that stainless-steel 1911s from Kimber or etc. would be preferred for this.

    Generally, pistol rounds have an effective range of 4 to 6 meters underwater. Beyond 7 meters, the bullet essentially is stopped by the water.

    Years ago I used a “ballistics tank” for firing bullets from handguns for comparison. It consisted of eight 55-gallon drums welded together into a tube 22 feet tall and filled with water. It was mounted vertically through two floors of our lab building. You literally fired the gun straight down into the “tank”, and a stainless-steel basket at the bottom caught the bullet. No pistol bullet, even from a full-power Magnum revolver, ever had enough velocity left after 15-20 feet of travel to be deformed when it landed in the basket, which was then pulled up by a chain, by hand.

    It occurs to me that, above water, the P11 would made to order for adaptation to MetalStorm technology, giving roughly ten shots per “barrel”.

    The potential rate of fire could charitably be described as horrendous.

    I suspect that would apply to the amount of noise it would make as well.

    clear ether


    • while the ideaof changing out the dart firing cassette for a metalstorm one to better be able to shoot above water is attractive and coukd certainly be limited to single fire instead of shooting everyrhing in a volley, just dropping the P11 and using a normal pistol or rifle is easier, quicker and bettet shooting firearms on land in general because thry were designed for that.

      • I was thinking more of a covert op that required underwater work. You’d carry the MetalStorm package in event somebody began doing things like trying to drop grenades in the water.

        Six rounds of nearly silent bullets would just irritate a boatload of “security”.

        Sticking a hand out of the water and unloading sixty rounds of far-from-silent Hell in their faces would tend to end the debate.



  6. Electric firing mechanism in a designated underwater gun. With the shelf-life of the batteries. I really cannot understand: why? Why did they choose to solve the problem of insulation, which must be perfect, or at least guaranteed for a certain time? It would have terrible trigger pull with a purely mechanical firing mechanism?

    • Electric firing solves both sealing, avoids rupture if the primer and protects against light strikes of submerged firing pins. For such a specialized gun, it is a feasible solution.

      • this plus combatdivers are going to put in fresh batteries into their other electrical devices like radios, torches, lasers etc. anyway. One device more is not going to hurt anything.

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