Shooting the Full Auto XM-8 Carbine

Thanks to H&K and to Trijicon for range access, we are out today shooting an original and authentic XM-8 carbine! The XM-8 family are relatively bulky guns; moreso than one would expect from seeing photos of them. However, they are also very smooth and comfortable guns to shoot, with a relatively low rate of fire that makes controlled bursts very easy.


  1. Please do a split screen when you dump a mag, and show the down range target. It would show what the spread is at that range.

    • Me too I’d like to see the results on the targets. See the shooting is cool, but how it spreads is good too. (Even a picture at the end of the video with all the shoots)

  2. Bulk is indeed a price paid for polymer; my complaint about all the plastic fantastic rifles. I thought it looked surprisingly compact in your hands, though.

  3. Everything seems to be right about this XM-8. There is some visible flex around receiver and barrel mounting, but that is to be expected with polymer envelope.

    • Polymer flex is interesting. Just as a dumb thought experiment, suppose someone made made a Maxim gun with a lot of polymer. Would they be able to scrimp on sandbags?

        • I meant to say shorter pegs. It just seems that a gun that isn’t very quiet internally might benefit from the dampening properties of polymer. Of course it may go the other way and bounce around more. In that case longer pegs and more sandbags would make more sense.

  4. Regarding the impression of bulkiness. This is probably due to arch over main body and transition leading into it. If it was not there, the contour would be lot slimmer. The usefulness of extra bulk is without a doubt, namely during impact at solid objects.

  5. I don’t like the reciprocating charging handle, which… Although it is covered by the carry handle/sight mount… As per Ar10, I think is a somewhat “cheap” design, regards its “out of space” idenity, and given it’s size/complexity in relation to said Ar; it may create clutter issues, mud etc.

    I have never liked this rifle, I don’t like the G36 either mind.

    I like the controls, mag/bolt release, bayonet, forward eject for lefties, but overall: No.

    It is so bulky, and that stock says flimsy to me, G36 polymer had issues obviously… Which may cloud my view with hindsight.

    An Aksu in 5.45mm is as controllable as that I think in full auto, and it is just 95% better in all ways bar say the controls.Hk going with the easy option of “Rotary” bolts, was probably better for business in that; that is the design used by Nato but it restricts anything other than cosmetic or functional developments.

    • Fluted chambers allow hot gas to hit the bolt face, this Ni-Ti “Nitinol” material could be used to actuate changing shape rollers, all kinds of stuff.

      • “Fluted chambers allow hot gas to hit the bolt face”
        Wait. Does they run whole length of chamber?
        According to my data, at least in ShKAS, they started at 10 mm from end.

        “this Ni-Ti “Nitinol” material could be used to actuate changing shape rollers”
        But temperature of elements of weapons might vary greatly, becoming much hotter after intensive firing.

        • I know, but theres open bolt cooling, forced air stuff… All good, better for Starship troopers than Plastic “laser” guns, alone.

          • “It does A at exactly temp 1 and B at exactly temp 2.”
            But do you can design your gun in way that given part would have appropriate temperature, all the time, in any conditions?

          • “Maybe the Blish lock could work, 100 years later he he.”
            Deliver more data regarding stiction of that NiTi.

          • “The friction which tends to prevent stationary surfaces from being set in motion.”

            With new materials. I meant.

          • “If your confident everything I have said can’t work, say it;”
            I do not say so.

            “Impossible, you do it.”
            Wait, you want to used together with Blish principle. Stiction is whole point of that system.

            “that is why I asked I.e. I don’t know.”
            I have feeling that you are not properly inventing. I must ask: are you following Altshuller’s rules? They are useful if you want to invite something new. To all unaware of them, this is good starting point.

          • Well… Your right really, I’m not, and it is a problem for me; really I just want to paint boobs being more of an artist. Still that was great info you posted for non boob painting, potential inventors.

            I haven’t mastered boob painting either to be honest.

          • Those Dennel type 20mm shoulder guns are probably going to be the future for anti robot “exo skeleton” puncturing.

            Bad kick though…

          • Basic example: Say we had a Ak107 with the counter recoil, but modified to have a tube one of these powerballs in it above the barrel; imagine its spinning “bang” off it shoots to the front, any use? I.e. It weighs more than originally now, and is put to use forward.

          • No Ar is going to pop a “Terminator” which are, certainly coming; they aren’t (alive) you see, and thus it presents living things with a bit of a problem.

          • “Perky aren’t they, know anything about that; Gyroscopic resistance?”
            For more data see inertial guidance system.

          • “No Ar is going to pop a “Terminator” which are,”
            Now I am totally confused.
            Yes you can use physic-powered gadget to lessen spread of bullets fired.
            But as long as cartridge is same and muzzle velocity is constant that will now improve penetration.
            So please choose exactly ONE from following list:
            – you want to increase penetration
            – you want to decrease standard deviation of point of impacts in azimuth
            – you want to decrease standard deviation of point of impacts in elevation

        • Blasted that mud out in the mud test on inrange and the cases are singed so it probably builds up a abit in said areas before it opens… Use deeper “rifling” I.e Grooves etc, ways possibly.

    • Anti German club, Aksu wins “ok that is shorter, but I mean… That makes its controllability so much more impressive” Good swing around your head, to bring it down on a Pickelhaube; it is just better.

    • Heat from direct impingement gas tubes, could hit a Ni-Ti ring around an Ar bolt which had a rear in the form of a collet, said collet could sit around a cone fixed to the carrier… Then when then ring constricts, the collet would squeeze against the cone thus forcing the carrier back without gas entering the bolt/carrier as per; which would rotate the bolt… Using fluted chambers may even enable you to remove the gas pipe, is it me or is this kind of technical change what we want for our Starship troopers not something that is pretty standard but looks futurustic.

      • “Ni-Ti ring around an Ar bolt which had a rear in the form of a collet, said collet could sit around a cone fixed to the carrier… Then when then ring constricts, the collet would squeeze against the cone thus forcing the carrier back without gas entering the bolt/carrier as per; which would rotate the bolt…”
        But could it work fast enough? After all in automatic rifle Rate-of-Fire of at least 600 rpm or so is required, that is 0,1 second cycle.

        • The cone would then force the constricted ring so collet back out, I see what you mean; I honestly don’t know, that is why I am telling you. Might work in semi…

        • How about a Nitinol pressure cartridge, idea is a mini light gas gun, but in a bullet… External heat “the new firing mech” causes the nitinol to expand, this forces a piston to compress say helium; then via burst disc, the projectile is fired. Apparently if you try to stop the transformation, it generates huge pressure because the atoms are just going to do what they do.

          • Probably “in principle” good for telescopic rounds, because the projectile could sit inside the “spring” so to speak; forward spring stops against chamber, rear piston compression against bolt… Burst disc in the middle beneath the projectile “bang” Needs work (can it work etc) I am not an NiTi expert.

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