MetalStorm 3GL Grenade Launcher: WOW!

While watching a video of the MetalStorm 3GL 40mm Grenade Launcher I was blown away by the incredible technology1 that these Australians have developed. I have blogged about the 3GL before, but I had not imagined it worked so well in practice. The video is worth 1000 words …

3GL Mounted Under M16 AR-15

The MetalStorm technology allows multiple rounds to be loaded into, and fired from, a single barrel. This makes a much more compact weapon than competing MGL2 systems such as the Milkor. The weapon has been designed to be within the same tolerances as the M203/M320 and so achieves similar range, velocity & accuracy. It makes use of standard 40x46mm grenade warheads which are inserted into the MetalStorm ‘tail assembly’. This would make the system much more attractive to nations which currently use the standard 40x46mm rounds.

The grenades are fired electronically as fast as the trigger can be pull and the barrel is capable of 720 rounds per minute! I asked Mark, MetalStorm’s armorer, about battery life and he told me that the 2xAA batteries is uses will last as long as the barrel does.

What really impressed me was how fast it could be reloaded. In the video you see the operator remove the rifle’s magazine when reloading – this was for safety and it not required in the field.

In its stand-alone configuration (not attached to a rifle and with its own stock) it weighs 5 lbs – less than half the weight of the 11 lb Milkor MGL!

Milkor MGL / M32

MetalStorm have also been working on a bullpup version of the 3GL. Aside from the shorter overall length, it allows the system to be used with rifles, such as the AK variants, which require the magazines to be rocked into place. The pistol grip of the non-bullpup version would get in the way during magazine changes,

3GL Bullpup. It is tiny!

As I said before, I am very impressed with this weapon. It offers a lot of power in a very small package.

Many thanks to David for answering my questions and providing photos and videos for the blog.

  1. (sorry about the lame pun) 

  2. MGL : Multiple Grenade Launcher 

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.


  • prodromos

    I think that the main problem of this launcher , must be the diferent ballistics of each individual grenade , due to diferent barrell lenghts . That would require diferent long range targeting for each round . Short range -<250yards would be OK .
    I allso think that this is not in the same category with Milkor .
    This is probably more suitable to replace the M203s .

  • 1. The grenades were dummy, not HE on the demo video, it have to be SAFE with actual explosive grenades.

    2. the barrel length, therefore the ballistics will be different for each shot.

    Otherwise interesting use of the old roman candle pyrotechnic device:-))

  • c trapp

    AFAIK the “Different Ballistiks for Each Shot” problem is addressed by adapting the propellant charge behind each round (I think I’ve seen this in one of their animations). The safety issue of stacking 40 mm grenades is not such a big one since the detonators of those work by inertia, not pressure. The inertial loads imposed on the shells by this system will be not much different from those generated by a revolver style system. (They will be higher due to the lower mass of the MetalStorm launcher but still in the same order of magnitude)

  • Clodboy

    I suppose you could get around the ballistics problem if they offered these grenades in pre-packaged stacks with gradually increasing loads to compensate for the different amounts of barrel length each one has available (which would, unfortunately, mean having to settle with the least amount of barrel length as the lowest common denominator).

    Alternatively, an electronic sight with a built-in ballistic computer might automatically adjust the calculated trajectory based on the amount of grenades remaining in the barrel.

  • jody

    that was very interesting.

    however i remain completely unconvinced on connecting 40x46mm grenade launchers to rifles. i already don’t think they add any effectiveness to the combined weapon. in fact i think putting these two weapons together actually reduces the effectiveness of both them. the m203 handicaps a soldier from my perspective. many nations have spent the last 20 years trying to develop combined rifle/grenade launcher weapons from scratch, from a clean sheet, and they never work out.

    i was excited about the 25x59mm grenade rifle:

    but it was cancelled. i still think this is something worth working on if the grenades can be improved. a 40x46mm grenade does not do that much damage, less than a hand grenade, so the 25mm grenade has a long way to go.

    but i still like the idea of getting the grenade launchers off the rifles and turning them into stand alone weapons only.

  • dogon1013

    Notice how the cadence of each of the 3 grenade shots changes.

    As each round is shot out, the round behind it has a longer effective barrel length than the one just shot, and the noise it makes when it is shot is slightly different. I’m curious if the balistic trajectory also changes, or if there is some sort of compensation built in for this in the electronics of the gun or round.

    Theoretically the last round shot will have the longest time in the barrel and should be travelling faster than the first round shot, if the pressure levels are the same for each round.

    Maybe it’s not that big of a deal with these low pressure grenades, but I am intersted if they have a way around this for there other products.

  • Mu

    There has to be some form of sensor telling the launcher which round to fire. If that sensor gets disabled in combat it might launch the middle or back round into a blocked tube. Sounds uncomfortable.

  • CMathews

    The thing I’d be worried about is an accidental in barrel discharge. Stacking HE grenades under the barrel of my rifle makes me cringe. And electornic ignition worries me too. I know it’s ran off of a small battery pack and it’s a very remote possibility but we sometimeshad problems when I was a welder if people welding on a vehicle next to suspension components like shocks and struts and arcing through the shaft. I know the voltage and amps dealt with on that level are much more than would ever be seen in the metalstorm, but it still seems iffy in my mind. Also, have they thought of powering it through one of those powered rail systems? Seems like a logical solution.

    But a+ for the ingenuity. Way to break the mold!

  • I asked their representative about (2) on the last Eurosatory.
    He claimed that the difference in muzzle velocity is too insignificant.
    That’s actually not implausible because the muzzle velocity doesn’t rise much any more after a certain barrel length. Maybe that’s why the barrel is so long – it may be necessary for the forward most grenade to reach that point.

  • SeanN

    the barrel length won’t matter that much; at 250 yds you’re already talking area target anyway, and your maximum effective range is 350-ish yards, depending on wind/elevation/etc, so we’re not talking minutes of angle here. i did 3.5 years as a grenadier, and i think it looks neat.

  • CS

    I would imagine they test them with explosive grenades.

  • CMathews

    I’m certain eventually they would test them with live HE munitions. You can’t sell a car if you never started after manufacturing it.

  • KP

    Overcomplicated solution to a non-problem. It’s a cool tech toy, but not useful.

    • KP, the problem is laying down fire. Single shots can currently be used, but they are single shot. The big MGL’s can be used but they take a while to reload, are are big and heavy. The 3GL allows semi-auto fire and quick reloading in a small/light package.

  • KP

    The weight comparison isn’t fair, you stacked the rifle-mounted version (5lbs) against the M32 (11lbs), which is an entire weapon system. The M320, on the other hand, weighs 3.3 lbs. 5lbs is a lot to hang off the end of your rifle! Three shots doesn’t make for much “laying down fire”, and the MGL puts out 6, if that’s what’s attractive. It also loads by moving forward, the same as the old M203. Part of why the M320 was attractive is that it swings out to reload for faster reloading and to accommodate the longer 40mm ammo. It’s a way-too-heavy 3-shot-but-slower-reloading under rifle grenade launcher that requires additional fittings for standard ammo. 🙂

  • Durham68

    I think MetalStorm should design their own stand alone version like the Milkor MGL. Make the weapon lighter and add capacity with the electornic ignition technology. Definitely need to produce pre-packaged stacks of rounds with varied loads to fix the ballistics issue.

    • Durham68, yes, it does come in a stand alone version.

  • mettandt

    Can’t understand there’s any comment about South korean K-11 rifle.

  • Carl

    This thread got me thinking about ways to build multiple shot grenade launchers.
    Have there been any attempts to use box magazines (AR layout) or tube magazines (shotgun layout)? Any semi-auto designs (other than crew-served weapons of course)?

    • Carl, there is one company that makes a pump action with shotgun like tube magazine 40mm grenade launcher (I forget the name). Small caliber grenades (20mm, 25mm) have come in semi-auto and bolt action fed from a box magazine, but this is not practical for 40mm just because they are so big. There are full auto crew served 40mm launchers that are belt fed.

  • Brad

    Very interesting!

    I think metalstorm has finally found it’s first practical application towards small arms technology. I was impressed that they have worked the system as separate fixed rounds instead of “pre-loaded” barrels. Compared to conventional under-barrel 40mm grenade launchers the metalstorm unit has obvious advantages.

    As for the criticism that the velocity would vary from the first to the last grenade fired in a loading…

    Even the old M-79 grenade launcher only had a muzzle velocity of 250 fps. It doesn’t take much barrel to achieve that much velocity, witness the ultra-stubby Soviet GP-30 40mm GL. The difference between the metalstorm first round and the last round’s velocity is probably lost in the noise of the random differences in individual cartridge loadings. In other words, no practical measurable difference.

  • Carl

    Why would the size of the 40x46mm grenade prevent it from being used in a box magazine?
    Would the general weight of the entire weapon including magazine be to large?
    Or are there other issues with feeding these cartridges from a box magazine? I guess they are kind of short and stubby but that doesn’t seem like an impossible problem to me…

    • Carl, there is no reason why it could not be fed from a box, but as you concluded, the size of the magazine and the weapon would be to big for practical purposes.

  • carl

    Well, the Milkor seems to be usable loaded with six shots. A semi auto or repeater with six shots box magazines would increase the firepower considerably I would guess.

  • Some Guy

    It’s 5 pounds with that rifle stock, so I’m thinking it’s probably around 3-4 lb without it. And given that the M203 is around 3 lb, I’m thinking that this thing is around 4 lb at least.

    As far as barrel length is concerned, it really won’t change much. The round is stored deep inside the weapon, basically where the firing system would ordinarily be, and so the extra length of the breech doesn’t really effect muzzle velocity or length of rifling, making the ballistics varied somewhat, but basically unaffected.

    Metal Storm showed one of it’s styled of weapon once firing three 9mm bullets right in a row, and they basically all the target in the exact same place at like 25 yards away (even though the first bullet had like 0 barrel length O_o). Supposedly, the firing system takes care of a lot of inherent problem you would normally find, and judging on how the NAVY supposedly bought a crapload of these in 2010, I wouldn’t doubt that it’s fully operational and has the kinks worked out.

    Problems I see is weight, bulk and ergonomics. The thing is a little bulky and, from the pictures, doesn’t seem to fit very well on the gun. Again, ergonomics is a kink that can be worked out (it can very easily be fit to the gun.

    What I really want is some A-grade specs on the device itself, just flat out weight and length, and then hopefully height, width etc.

    What the weapon proposes to do is amazing, that is give soldiers a 3 shot semi-automatic grenade launcher weapon attachment, allowing a solver to do, essentially, what the M1 garand did to bolt action rifles; allow follow up shots.

    I can imagine three of these things allowing a single soldier to wipe out an entire squad of enemy units in just a few seconds, or less. Mixed with some semi-auto spray anyone caught out in the open is practically toast.

    Again though, I’m not sure how effective it will be if it’s too long, too heavy, and too weird feeling, I.E. the ergonomics are just plain off. Specs would be amazing if anyone has them or knows where to find them.

    Also, I’m not sure how well one of these would fit on a M-4 Carbine, which is what the Army seems to be adopting and what the Navy (Navy Seals?) generally tends use a lot with infantry, but I can see it as is getting a lot of use by marines.

    From the looks of it, that thing has got to be around 20 inches long, and unless they can get it down to around 14.5 inches, I don’t see it having much use in the Army or the Navy as a “Future Weapon”. Who knows though, maybe they made the barrel really long just because they could (on the M16, for instance) and maybe it’ll work well with smaller weapons, we’ll see.

    Whatever the case, it is definitely a big stepping stone, and a hope for the things to come.

  • Some Guy

    “Well, the Milkor seems to be usable loaded with six shots. A semi auto or repeater with six shots box magazines would increase the firepower considerably I would guess.”- Carl

    Well the minimum base diameter of a 40mm grenade would have to be at least 40mm, so a 6 shot 40mm grenade launcher magazine box would have to be at least 240mm long, and probably well over 250mm (what with the spring and top-loading part), which is about .8-1 foot.

    The weight of each 40mm grenade is about .5 pounds, so the magazine would have to be about 3 pounds+, if not 3.5-4 lb.

    The magazine would also have a minimum width and length of about 4 inches long and 1.5 inches wide, and probably far larger.

    Modern drum magazines have problems loading even 100 round 5.56mm rounds, which is about 2.7lb, so loading 3lb would either require a spring that was too hard to hand load or, unreliable. Either, it would probably wear out quickly.

    The magazine would not fit into any conceivable available ammo pocket or pouch and would be more difficult to carry around than the bandoleers that our current soldier’s wear. The box magazine would also be relatively unreliable, heavy, and and increase the weapon system using the clips weight drastically, a semi-automatic firing system being vastly heavier than a revolving system.

    While possible, a 20 pound weapon system using 4 pound magazines that 4.5 x 2 x 12 inches would be ridiculous. Not to mention that it would jam all the time, be unreliable, and even in use, be hard to use.

    It’s probably better that the milkor is revolving, instead of semi-auto, so that it can actually be used easily be human beings.

  • elseagoat

    Someone above me said the XM25 “Punisher” program was cancelled.

    I had read that this weapon has already been fielded for testing to some units in Afganistan, and has been used to good effect (no confirmed kills likely due to longer ranges that it is used at, but enemies have abandoned emplacements when weapon is used very quickly.) Basically, I heard the project is pretty much going strong and looks pretty good so far.

  • Jersy

    As far as 3GL is concerned, I don’t really know how it’s going to work out in the end as accessory grenade launcher… Although I read some stuff here and there stating that it’s not going to be that much heavier than M203, and that the advantages outweigh the disadvantages etc.

    In fact, I see more potential to this technology in stand-alone configuration. Stand-alone 3GL seems to be a nice little compact thing. But more than any promotional video or statement, the words that drew my attention the most were the following (in description on

    “Converts quickly to stand alone weapon including dual barrel option for mission specific needs.”

    Dual barrel option… Wow… Think Sage Ordnance Systems Deuce (Over/Under Dual 40mm grenade launcher), but with six shots total (2x 3GL = 6GL). Sadly, it seems there are no pictures available of this configuration.

    So far, I haven’t done the math on weight and stuff, but it seems to me like it could be more compact than any revolver-based six-shot grenade launcher. Plus, really intimidating look with two barrels plus the theoretical ability to fire two grenades at the same time, for extra punch…

    However, I would take it a step further – I envision a Metal-Storm based stand-alone grenade launcher in M202 FLASH-style configuration… Four barrels in 2×2 setup. Now, since the very platform has changend and increased in size, it could certainly be able to accomodate more grenades per barrel. As far as technology goes, it seems like some of Metal-Storm 40mm designs are capable of having up to 6 40mm rounds stored in each barrel… While that might be taking it too far for a man-portable weapon, 5 or even mere 4 rounds per barrel would make this weapon 16-shot grenade launcher…

    Maybe I am thinking about it more in the “That would be so cool” way, but I can’t help but think that it might have an application or two (one of them being carpet grenading).

    Although probably not exactly suited for modern urban combat… But hey, if you are supposed to carry standalone grenade launcher, make it as much size-weight-firepower efficient as possible.

  • Waters Under Earth

    Now increase the capacity and combo with a bullpup rifle…. like I thought of somewhen last century….