$52 MILLION Contract Issued to Vista Outdoor for Mk. 311 Ammunition by US Army

Alliant Techsystems’ (ATK) spinoff company Vista Outdoor has won a contract worth $52 million for Mk. 311 Mod 3 frangible ammunition to supply the US Army, with a completion date of June 22, 2022, according to the June Department of Defense contracts press release. The contract is likely for 100 million rounds of ammunition or more, which will probably be used mostly for training at ranges with limited backstops.

Sectioned 5.56mm rounds. In the center is Mk. 311 Mod 0 Frangible, which uses a 50gr bullet with gilding metal jacket and a frangible copper matrix. To its right is Mk. 255 RRLP, which uses a 62gr bullet of similar design. On the far right is the 70gr TSX “Brown Tip”. Image credit: Wolfganggross, used with permission.

The Mk. 311 round – better known by its ordnance code “AA40” – is loaded with a 50gr frangible bullet, identifiable by a purple tip. The projectile is make of a lead free powder matrix, wrapped in a gilding metal jacket. It is similar to the Mk. 255 Reduced Ricochet Limited Penetration (RRLP) round, which has a heavier 62gr bullet. In addition to being used in training at ranges where more robust projectiles might damage the backstops, both Mk. 311 and Mk. 255 see use in special operations both because they reduce the chance of ricochet in close quarters (such as on a ship) and because they offer increased lethality at short ranges.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


  • John

    What is that which has a hollow core on the right side? That’s deep!

    • CommonSense23

      It’s the 70gr TSX. It’s the Bin Laden bullet.

      • Nicks87

        Is it the same as the Barnes TSX solid copper bullet?

        • milesfortis

          Exact Same Thing.
          It was designed by request of certain SOF units.
          Uncle ceded open marketing rights to Barnes so they could recoup research and development costs.
          Barnes also makes the 62 gr RRLP bullet.

          • Sunshine_Shooter

            I’m going to have to test some Barnes TSX in my AR now, see if my barrel likes it.

          • milesfortis

            Be advised.

            Minimum rifling twist is 1/8 in 16″+ barrels, maybe in some shorter barrels as well, but 1/7 is what’s standard for Uncle anyway.

            It will not stabilize in any known reasonable length of 1/9 twist barrel and keyholes @ 25 meters.

          • Sunshine_Shooter

            Is that for all 70+ grain projectiles, or these specifically?

          • milesfortis

            For the TSX, as you had advised you were going to shoot.

          • Sunshine_Shooter


          • milesfortis

            As I hope I’ve made clear, “Your Mileage May Vary” for anything other than what I’ve specified.

      • John

        Oh yeah. Now I see it. Solid copper. Thx.

  • Audie Bakerson

    “The contract is likely for 100 million rounds of ammunition”

    Or 5 million rounds of Monster Control Bureau silvered 5.56

    • Agent Franks


    • Sunshine_Shooter

      I want to believe.

  • CommonSense23

    RRLP is reduced richochet limited penetration. Not Reduced Range.

  • Analus Rubhammer

    Aren’t we supposed to find out some test results for a successor 7.62 Nato gun or adopt a new 5.56 successor we will adopt in the next month?

    Just in April/May, I was reading several articles about the Army abandoning the M4/5.56 platform/caliber..? It seems like the 7.62 is what needs a replacement with these “prophetic” 6-7 caliber’s.

    • Some Rabbit

      Did you really fall for that clickbait? No way NATO is dropping the 5.56mm (anymore than the US going back to the .45 ACP)

    • Sunshine_Shooter

      That’s some high-level brass who have no idea what they are talking about. That will never actually happen, and if it does, then it will be US-only. 5.56 is a far superior cartridge for the kind of fighting that happens in real life, and any sort of halfway realistic trial or testing will only make that more apparent.

  • Aaron

    Glad I bought shares a while back

  • Simple

    It has an EPR like jacked, do you see the 45° angle the jacked ends near to the nose? When it enters tissue, pressure rips it appart there.

  • CommonSense23

    I spent a lot of time around MK255 and have seen it’s use in live tissue alongside 70gr brown tip, MK318, and 262. And 255 consistently outperformed those other rounds in terms of just live tissue.

    • Zach Robinson

      What was the penetration depth? I also suppose I should ask what lab did the testing and if it was performed on pigs/other human analogs. If we’re talking about recovering bodies of Johnny Jihad and Terry Taliban that could be slightly different, especially if one were to only observe the superficial wounds visible to the naked eye. Scientifically it’d be quite the feat to observe multiple rounds tested side-by-side, and observe immediately which projectile performed most ideally in live tissue; ethically, however, maybe not so much.

      • CommonSense23

        It was live tissue training on pigs. We always did various round testing on pigs that we wouldn’t work on. So about 10 pigs laid out, asleep obviously. Go down the line 255 in one pig, mk318 another, 70gr in one. And so on. Various locations each pig. With pig on its side was able to penetrate ribs and destroy the heart. Its performance was drastically different than the other rounds. You just pay the price that it sucks at anything other than soft tissue performance.

        • Zach Robinson

          I spent a little while looking through any/all resources I had saved from Dr. Gary Roberts on the subject and it appears the IWBA arrived at the same conclusion more or less. Soft tissue damage is amazing but the ability to repeatably penetrate a particular depth was wanting, however when it did penetrate enough to strike a major organ the results were devestating. If I recall correctly the DOE has used the Mk255 around nuclear facilities for some time.

          • Sledgecrowbar

            So… with an advertisement like this military contract, this is going to be the hot new home defense round for piehitters who insist on using an AR for home defense? Hopefully someone makes video of drywall testing.

          • Outside a shotgun loaded with small shot, ARs are among the least penetrating guns you can use due to the fragmenting nature of most rounds.

            They are excellent home defense guns even if some people have jumped the shark with them.

  • Destro Yakisoba

    Are there any declassified gel tests of Mk311 or Mk255 hahaha? Or any done by amature gel experts?

  • demophilus

    Anybody have any idea how the 255, 318, etc. perform on impact with AK magazines in a chest rig? Something that shatters on a steel plate or barrier might penetrate a mag before it dumps energy.