PNW Arms Supercavitating Rifle Ammunition

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PNW Arms is the latest company to develop a supercaptivating rifle bullet with the ability to deeply penetrate water. See this impressive demonstration …

To quote Wikipedia, supercavitation is “is the use of cavitation effects to create a bubble of gas inside a liquid large enough to encompass an object travelling through the liquid, greatly reducing the skin friction drag on the object and enabling achievement of very high speeds.”.

During the 70s, Russia developed torpedoes that used supercavitation which allowed them to travel much faster than would otherwise be possible. Since then Germany and Iran (or so they claim) have developed similar torpedoes.

[Hat Tip: Solider Systems]

[ Many thanks to Nugroho for emailing us the link. ]


Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


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  • Giolli Joker

    Interesting!
    GS Custom bullets claims to have their own supercavitating bullets: http://www.gsgroup.co.za/articlepvdw.html
    There are even studies in the US to develop some sort of high speed supercavitating submarine to transport spec ops soldiers.

  • bbmg

    Impressive test, but it does seem to be a bit over specialised. Shipborne defense from divers perhaps?

    Aerial mine clearance seems to be a good avenue for such ammunition: http://www.as.northropgrumman.com/products/ramics/index.html

    Even so the above approach seems to favour saboted darts.

  • noob

    there is a lot of energy transfer to the water, making some of the gallon jugs jump. what was the initial velocity? how much does the brass projectile weigh?

    • Mike Knox

      The jugs just bounced because of the secondary wave off the board caused by the hydrostatic shockwave..

  • http://www.blogger.com/profile/01371257387692776351 Alex Nicolin

    The Russians did it a long time ago.
    http://world.guns.ru/assault/rus/ads-dvuhsredny-e.html

    • Roy Rapoport

      Not quite.

      The obvious, easy, way to make your projectiles go further, faster in water is to lower the cross-section — make them more spear-like (this is why underwater fishermen hunt with spears rather than throwing stones at their fish :) ).

      What the Russians did a long time ago was create specialized rifles (the APS series, http://world.guns.ru/assault/rus/aps-underwater-e.html ) which used special magazines to store cartridges with very long, needle-like projectiles (the projectiles were 12cm, or 120mm, or about 4.7 inches long).

      More recently — in the last 7 years or so — they’ve come up with a new rifle (the ADS you refer to) and new ammunition (5.45×39 PSP) which obsoletes the APS. So that’s awesome, because the 5.45×39 PSP is sufficiently externally similar to the other 5.45×39 loadings that they no longer need to use specialized magazines.

      However:

      1. It’s not all that “long ago” :)

      2. More importantly, it’s still not super-cavitating. It’s just got a super-high BC (because the projectile is still abnormally long — remember, it reaches all the way back to the base of the cartridge), as a way to go as far as possible in water. Super-cavitating cartridges such as the above would probably actually measure a super-low BC because with that blunt nose, they’re creating even more resistance against the water until the water goes gaseous and they’re essentially travelling in their own little air bubble.

      That said, it’s worth noting that the ADS is designed not simply to be shot INTO water, but to be shot IN water. That’s likely an advantage, if you’re a military force interested in that use case.

      -roy

      • http://www.blogger.com/profile/01371257387692776351 Alex Nicolin

        The 5.45×39 PSP is presented in the diagram with a flattened nose, needed to induce supercavitation not a sharp or rounded one, needed to achieve the a high BC. This diagram may not be accurate. Nevertheless, the bullet presented there is 9.5 calibers long (53/5.6), which is way too long to be spin stabilized in air. It would need a twist rate of 1 in 3″ to be aerodynamically stable (see Greenhill’s formula) . The longest practical bullets that can be spin stabilized are 6 to 6.5 calibers long. Additionally, water is ~1000 times denser than air, so the spin rate should be ~10 times higher in order to keep the same projectile stable in water. In conclusion, the twist rate would have to be 1 in 0.3″. That’s not rifling, but a thread, and no bullet could be fired trough such a barrel without blowing it up. The bullet is not drag stabilized either, as there could be no fins that would be able fit trough the barrel, and be effective at the same time. That leaves out both spin and fin stabilization, but there is another possibility – supercavitation itself: http://www.gsgroup.co.za/articlepvdw.html. If the bullet is supersonic, there could be also supercavitation in air, which would keep it stable for a few dozen yards.

    • http://www.thefirearmblog.com/blog/ Steve (The Firearm Blog)

      No, those rounds are not supercaptivating.

      Supercaptivating means a bubble forms behind the tip of the bullet/torpedo so most of it is not touching the water.

  • Reverend Clint

    Great Red Jacket will have a special SEGA for hunting fish or some crap

  • Doug

    Is it primarily a naval application? I could see it doing some good damage on thinner hulled pirate ships, or the much boasted Iranian speed boats (should the opportunity present itself).

    • bbmg

      How about an underwater gun turret, seems to be something in the pipeline. Here’s a patent: http://www.google.com/patents/US5911172

      From an online article about supercavitation:

      “The next step in supercavitating projectile technology will be an entirely subsurface gun system using Adaptable High-Speed Undersea Munitions (AHSUM). These would take the form of supercavitating “kinetic-kill” bullets that are fired from guns in streamlined turrets fitted to the submerged hulls of submarines, surface ships or towed mine-countermeasure sleds. The sonar-directed AHSUM system is hoped to be the underwater equivalent of the U.S. Navy’s Phalanx weapons system, a radar-controlled rapid-fire gun that protects surface vessels from incoming cruise missiles.”

      You could also conceivably provide this type of ammunition to the Phalanx or Goalkeeper platform which in conjuntion with sonar could defend against approaching torpedoes, or prematurely detonate moored mines.

      • doug

        Wow, I had no idea. Thanks for the info.

  • scb

    Here’s the russian ADS with a supercavitating bullet.
    You can see it actually being shot submerged at 2.23. As well as the bullet travelling underwater in SLO-MO. Strange that you have missed it

  • bbmg

    From the defense review article on the DSG rounds: http://www.defensereview.com/dsg-technologypnw-arms-multi-environment-ammunition-mea-solid-copper-general-purpose-supercavitating-gps-and-tungsten-penetrator-tipped-dual-core-supercavitating-dcs-armor-piercingarmor-penetr/

    “At NDIA Joint Armaments Conference, Exhibition & Firing Demonstration 2012, Mark Baciak of PNW Arms showed us production samples that PNW manufactured right here in the USA that are “ready to be shipped domestically and worldwide”. So, the new DSG Technology/PNW Arms supercavitating/underwater rifle ammo, including AP rifle ammo (armor-piercing/armor-penetrating rifle ammunition), part of a DSG/PNW “fused project”, is now Berry-compliant.”

    It would seem this is the same round.

  • tarkan

    Kursk was about to use supercavitating torpedoes and Dallas intervened??we may never learn the truth,but it was a one shot away from ww3.

  • dpaqu

    Anything shot into the water at thousands of fps is going to supercavitate. Anything that makes the cavitation happen earlier is going to lower friction given the likely speeds we are talking about.

    I don’t think this is all that exotic.

    • Mike Knox

      The idea of supercavitating points is to generate a pressure cavity on the leading surface. Conventional rounds generate the cavity at the tail end. The idea for this one is to put it ahead of it’s centre of gravity.

      If you still don’t think much about that, read around for 1970s-1980s NATO projects for supersonic torpedoes or Soviet Ionising cavitation fuselages for aeroplanes/foils..