This looks like a whole lot of fun to shoot. It is based off of the G3 rifle and made select fire and belt fed. It can use an adapter to allow the use of G3 magazines or drums. This one looks to be an H&K 21 chambered in 7.62x51mm. There are other versions in 5.56x45mm and 12.7×99 aka .50bmg. I can’t imagine a .50bmg belt fed H&K 25. That seems monstrous. The rate of fire for .308 is only about 800 rounds/min where the .50bmg is 450 rounds/min.



  • Joe

    I remember reading somewhere that some units in SOCOM (maybe SEALs?) used the HK21 in the not-so-distant past.
    The MP5 gets all the love, but I think this is much more alluring.

    • Martin M

      Anything belt fed is more alluring.

      • Anonymoose
        • iksnilol

          My ears are ringing from looking at that thing.

          • Anonymoose

            Noveske makes a KX3 for HK rifles, I think.

          • Flounder

            That’s just the sound of freedom man.

        • Ebby123


        • Gus Butts

          The Vollmer MC51B is very high in my “top 100 firearms I must try out before I die” list.

        • Anomanom

          Saw one of those for sale at a gun show a while back. Didn’t ask how much it was.

      • gunsandrockets

        I have to admit, that the 9mm belt-fed AR upper is very cool.

    • Richard

      Delta force apparently used them to a degree.

    • Udy

      1st SFOD-D still got them

  • Richard

    I. Really. Want. One.

  • Ron

    Only fired them a few times before, they are real accurate for a belt feed weapon but they also recoil quite bit more than heavier traditional belt feed weapons. I understand why some people refer to them as jackhammers.

    • John

      I’ve seen a lot of them fired in full auto.

      They’re sexy as hell, but they beat themselves to pieces.

      When they run, they’re the best thing around. They just usually can’t run very long without stoppages.

  • Andrew Miller

    My local FunStore has one for sale.
    It’s $35K but Transferrable.

    I need to win the Lotto and buy both it, some barrels, and a pallet of ammo.

    • Ebby123

      $35K?? Thats it?

      • Andrew Miller

        I haven’t checked on it recently, but it’s been a “drool” item for over a decade now.
        Thanks a lot, now I’ll have to head over there one day and see if she still beckons to my wallet.

        They had a set of 1921 Thompson SMG’s for 55K each, does that sound better?

        • RICH

          I waited a long, long time to find a Thompson I could justify buying. I almost crapped on myself when I told my wife (God bless her) what I wanted….and then she said, ” go ahead and get it if that’s what you really want ! !” I did and they can be found if you look hard…. !

          • Wolfgar

            Your wife is a keeper 🙂

      • mbrd

        far out! that’s scarcely more than i’ve spent on my last three vehicles…

  • TheNotoriousIUD

    Thatll keep the neighbor kids off your lawn.

    • MisterTheory

      I like you.

    • Uniform223

      No you need an M1 like in that one movie with one guy and that kid…

      • aevangel1

        Gran Torino with Clint Eastwood…

        • Uniform223


          • aevangel1

            Great movie!

    • aevangel1

      You’re an infamous birth control device?

  • Rnasser Rnasser

    There is no HK21 in .50 BMG…

    • Nicholas C


      • Rnasser Rnasser

        Was an HK25 ever built?

        • Brick

          I think protos were but never full production.

          • Rnasser Rnasser

            I’ve seen drawings, but never a picture of an actual HK25, even in prototype form.

    • HH

      Never seen one or heard of one….sure there may have been some weird prototype , a one-off… but I’m around a lot of HK guys and MG shoots and have never come across one.

      I’ll put a plug in for Michael’s Machines. He makes beautiful HK21e and HK23E American made “clones” of the factory guns. Superb craftsmanship. In fact most of the 21e/23e’s you’ll ever see being shot are his builds. I’ve enjoyed mine immensely. They make excellent registered sear hosts.

  • Tyson chandler

    I heard somewhere that Delta Force carried this on the ill fated Iranian hostage rescue mission. Anyone know anything about this?

    • Billy Jack

      Definitely calling that a Jimmy Carter from now on.

  • JumpIf NotZero

    Had that trigger pack, best one HK made. A little sad I got rid of it, but if Brethren Arms ever gets their AR trigger together that will fix any problems I have.

  • SP mclaughlin

    I can never figure out how you are supposed to load this, or if fires from an open bolt.

    • Giolli Joker

      Closed bolt.

  • Daniel

    I talked to a dealer today about the same gun. He said all but new. $40K. I am out. Trumps going to repeal the NFA act. Cheap transferables for all!

    • MichaelZWilliamson


      I hope you’re being sarcastic, otherwise you’re a turnip.

  • MisterTheory

    I have always loved the G3/HK91 series, and owned an early HK91 until I foolishly sold it to pay bills so my wife and kids could eat. I really miss it. I really want one of these as well. Just beautiful.

    • Billy Jack

      Stupid kids are always trying to starve when you’re trying to buy some cool stuff. I hate that. Next time they do that I’m going to send them to bed without dinner again.

  • mechamaster

    The most interesting feature of H&K 21 is the capability to do the Quick-Change Barrell… And maybe the caliber conversion capability
    It’s like “closed-bolt” MG-42/MG3 ( but with non-recoilling barrel ) and more easy to do the QCB without the hand protector / asbestos glove.

    • HH

      And to one-up that is the HK 21E/23E series… at least as built by Micheal’s Machines. You can swap out the feed mech, barrel, and bolt group in all of about 2 minutes…so you can shoot 308 or 556 beltfed.

      Now that is cool

  • RICH

    SWEEEET ! ! I’m happy with my ’28 Thompson, though…. !

  • Klaus Von Schmitto

    $12K will get you a new build HK21 Belt fed. You can find a trigger pack later for it if you want the full monty.

    • HH

      12k gets you a new built clone version.

      or you can buy an old used 21 build off factory parts for about the same…12k.

  • roguetechie

    Technically that’s a 21e… And yeah the 21e/23e convert to the other relatively easily. 23e is 5.56.

    21 and 21a1 were the ones where the belt feed unit slipped through a cutout in the magazine well area.

    Unfortunately like multiple people pointed out they beat themselves to death.

    Also unfortunately, they don’t use the standard HK trigger pack so AFAIK moving one trigger pack between a bunch of other HK host guns isn’t really an option like usual.

    If you want a semiautomatic version though Michael’s Machines makes them and I believe it’s even sub $15,000 for a setup with 5.56&7.62 feed units and barrels.

    • HH

      Correct for the most part but it you are a sear owner then you can indeed easily swap the pack around to other host guns. I do just that. The pack’s hammer needs to be timed and the ejector lever cut out on the pack frame cut a bit deeper….but after that …that registered pack can be used on all hk semi hosts for the most part. It’s easy.

      The new MM23E runs about $11,500. You can get the 21E 308 hot swap kit for another $4-5k for that gun too.

      • roguetechie

        Good to know…

        In my study of HK guns and the 21 21a1 xm262 21e and 23e manuals including armorer manuals the one thing made very clear was the trigger packs were somehow non compatible because of the extra “tail” on these that’s not present in the other guns.

        I was lucky enough to run a full belt through a 23e once, but other than that and using HK & CETME trigger packs and other parts for my hare brained home builds, and several hundred dollars in MP5 MP5Sd & MP5K rentals is the total of my HK experience.

  • Roland_1911

    I could only describe that as “hate sex”.
    Spewing hate and it feels so f*%$ing good.

    • aevangel1


  • SP mclaughlin

    I actually have seen that video, I just want to see a more complete showcase. Hopefully an HK21 derivative will show up on Forgotten Weapons sometime.

  • Adam

    Wasnt Vollmer ??? building cut down MP5 sized belt fed HK21’s back in the 80’s

  • Evan

    I saw one of these for sale at a gun show once. No price tag, it was one of those “if you have to ask, you can’t afford it” type things. I had to ask, and couldn’t afford it. What a shame.

  • Well the rate of fire sounds adequate. Wish I could get one, (sigh)…

  • Jerry Sullivan

    H&K build some damn fine weapons. Should have been paying attention back when Vollmer was manufacturing them and they didn’t cost more than a new home! I have mixed feelings about the roller lock bolt, rather dirty in the throat but works very well.