STK Ultimax 100 MK 8

The last time we discussed the Singapore Technologies Kinetics (STK) Ultimax 100 machine gun was back in 2008 when General Dynamics unveiled the Ultimax 100 Mk5 as their entry into the Marine IAR competition, a competition eventually won by the H&K M27 IAR. At the Singapore Airshow last week, STK unveiled the Ultimax 100 MK 8.

Photo from Trishul

By all accounts the Ultimax 100 is a fantastic low recoil machine gun, but it was positioned in lonely space somewhere between automatic rifle and belt fed machine gun. It looks like STK is now aiming squarely at the automatic rifle market.

[ Many thanks to Ron 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.


  • Anthony

    That’s a nice looking rifle and the ergonomics look like it would be a nice shooter (judging from picture as I don’t have one in hand), but the blocky-ness makes me nervous on that. It looks like it’d be a heavier weapon.

    • jagersmith

      Approximately 10.5 lbs without the optic, compared to the USMC IAR at 8 lbs and the SAW PARA at 15 lbs.

      • Avery

        Back in the early models, when they only used the 100 drum magazine, the Ultimax was more of contender for the SAW. The recoil is so light and gentle that the ST Kinetics sales team will demo the thing by doing a magdump, on full auto, with the butt braced against their chin.

        I’m pretty sure everything passed Mk 5. is USGI-compatible and is meant to be used with something like Beta C-Mags.

  • lex

    This gun gets hyped so much by most of the places that talk about it that I immediately become skeptical of how good it really is.

  • Vitor


  • Now this is a rifle, not a tacti-cool Bull-pup, those pathetic attempts at being a shooting ladies handbag.
    Real wars, with real Soldiers, need guns that do not get in their way, the enemy already does that, really nice.

    • Lao Ah Soh

      Sorry Eddie, we aren’t the enemy! Singapore is not China. We’re more like Chile without Pinochet, natural resources or land. Or cold weather. Scrap that, we are not like Chile, but we buy mostly American, British and French kit and we’ve got the only naval base/port of call in the East-Asia region capable of servicing Nimitz-class carriers. Which it frequently does. It also builds oil rigs.

  • KNF

    Having used an earlier version (the Tommy gun-like Mk.II) during my military service I can say that it is indeed a very good shooter, thanks to James Sullivan’s (he of M-16/AR-15 design team fame) constant recoil design.

    It is a rather heavy weapon, being made out of sheet steel stampings, and earlier versions had somewhat suspect welds, but later versions are relatively solid and the magazine well and catch looks improved in this version.

  • LockLoke

    Had the chance to handle it at the Airshow. The STK guy told me that this is a prototype they put together for the airshow and they were still working on improvements, especially on losing weight. Also, you may want to note the stock is now extendable instead of folding. Looks like it will be a bit longer before we see the final version.

  • Michael

    So we have a pretty heavy rifle with very little rail space, and an awkward stock that makes for a suspect cheek weld based on the height of the optics?

    Why do people keep trying to reinvent the M4 by throwing more crap on it that does less of a good job?

    • Tinkerer

      It’s a light machine gun/squad automatic weapon/automatic rifle. It’s not a chopped rifle like the M4. Different concept, different machine.

  • mike

    as long as nothing really changes with the stroke and bolt group I am all for whatever it takes for this weapon to reach the masses. I don’t know anyone on the planet that has shot all the options that has anything but praise for the ultimax. Step outside the box and maybe ask someone who has everything and has shot them all which is the best shooter. This is the shoulder fire machine gun. The Stroke extension is the absolute key. bom bom bom. Very slow shooter with the lowest recoil ever recorded by a an assault rifle much less a machine gun. It was made high cap first, which was maybe its demise, but now having a magazine well for standard mags maybe it will achieve higher circulation. I truly love this weapon and think the world needs to set this as the standard for Ultra light machine gun/Automatic rifle. Automatic fire while on target is achievable. Its a short stroke piston much like the other AR’s that are coming except it was designed to be so the carrier is supported properly. This gun is the truth.

    • noob

      Since the Mark V, the ultimax has had a closed bolt semi auto mode. I hope that this one retains it.

      A pal in the sg army NS had some problems with carrying an old broken down Ultimax in open bolt mode, due to a worn out safety – it would slamfire whenever he jumped off obstacles on the blank fire training. In the end his officer made him take out the magazine and hold on to it, only loading it to fire.

    • chino

      I served in the SAF mid-80’s and the next ten years as a reservist. Today, everything about the SAF has changed from the helmet, to the rifle, to the boots, and to the vehicles they ride in.

      The only carry over from my time?

      The Ultimax 100.

  • Hiram Maxim

    Nice Improvements and evolution!

    I think the biggest one is the vented heat shield over the barrel and the STANG mag well carried over from the MK4!

    IMHO The barrel being exposed to the shooters hand and the older magazines(MK 1,2,3) lock-up was the weak points of the system.

    To those that have never handled/shot an Ultimax 100 its very light weight and very very controllable,smooth shooting and incredibly accurate. If You ever examine one in detail there is a tremendous amount of thought that went into this weapon System.

    I’m not totally sold on the barrel extension/locking lugs being a fixed part of the trunion in the receiver.(this is what the bolt locks into as well as the QC barrel)

    From an economical prospective I can see why, however if the extension is damaged the gun is scrap metal.This is also true of the interrupted locking locks that lock the barrel into the trunion. (see the BREN LMG)

    It would be nice if STK or General Dynamics would support the older models, as parts are hard to come by! hint hint wink wink!

    Cheers, Hiram

  • Alex

    I hada chance to handle it at the Singapore Airshow and I must say that it’s a lot heavier that mk3s that I have handled before.

    • jagersmith

      With or without the optic?

  • Philip

    I am Singaporean. I was in the army, where I was issued the Ultimax 100 occasionally. I have also handled the subsequent marks of the machine gun. Here’s my take.

    There are good reasons why the Ultimax 100 never took off in a big way. The only good thing about it was the constant recoil system, which accounted for its light recoil and accuracy. Other aspects of it simply sucked.

    Take the magazine. It started out using only the drum. Problem was, it was difficult to load the drum without a special mechanism issued only to the armourer. Hand loading the drum was a pain – literally.

    This led them to issue specially modified M16 magazines. Problem was, the magazine was secured to the gun by two shallow holes right at the feeding lip. The magazine would drop out of the gun if the soldier handled the gun without care. The gun would also become a jam-o-matic if the magazine feed lips were the slightest bit damaged – which was almost inevitable given that the left feed lip was already compromised!

    Until GD began collaborating with ST Kinetics, this issue was never solved. Finally, GD probably told ST Kinetics that no one will buy a weapon where the feed system was so poorly thought out, and forced ST Kinetics to accept that they have to go all the way to have a mag well suited for M16 magazines.

    Problem is, by the time that happened, there were better designs out there that offered the same low recoil and greater accuracy because they were based on rifle designs. The Ultimax 100, accurate as it was compared to other 1980s designs, could not compete with genuine IAR designs such as those offered by HK or LWRC.

    • chino

      One can’t reload linked ammo belts either without spending a crazy amount of time, but that hasn’t stopped people using belt-fed guns.

      So this is the first time I heard that SAF stopped issuing drums because it was hard to reload by hand. I’ve heard other reasons like the drums having a habit of being easily detached from the weapon, jamming etc. I guess we’ll never know the real reason and SAF is always tight-lipped. However, in the pictures I have seen of the Ultimax’s use by other countries, they seemed to prefer the drum always.

      Another thing you are wrong about is that the Mk4 entry into the USMC IAR trial had a STANAG (M16) type magwell installed because it was a USMC requirement that the weapon uses stock STANAG magazine. The Mk4 had the magwell as an adapter that can be taken off so it can still use the Ultimax proprietary 100-rd drum.

      Not because “GD forced STK” etc. Gee… where did you get that?

      Finally, the two holes were drilled onto the side of the magazine near the feed lips, and not drilled “right at the feed lips” as you so erroneously wrote!!!

      And IMO, the two holes did not lead to the feed lips being easily deformed. El Cheapo soft aluminum STANAG mags used by the SAF are prone to feed lips deformation by default, even if you so much as dropped a loaded one that happen to land on its lips, PERIOD. That’s why there are so many alternatives offered on the market in the US like P-mags etc made of either harder metal or non-metal materials. The Brits, IIRC, use HK steel mags, not aluminum. And bent feed lips are the major cause of stoppages in not just the Ultimax but in the M16 as well.

      Please get your facts right.

  • TOM D

    it will better if STK into a bomb chain for bombs

    • Brian in Seattle


  • chino

    I have fired the Mk 2 & 3 on several occasions while serving in the Singapore military. Needless to say, I love this weapon for its simplicity, lightness, low recoil and accuracy – if a tad flimsily built. (It’s the only sheet-metal stamped weapon in Singapore use.)

    I see this latest incarnation is nothing more than a IAR since, with the mag-well, you can only use STANAG mags. And the mag-well makes designing a drum a problem as evidenced by the Beta C.

    Having said this, the drum concept had its drawbacks.

    With the Mk 2 & 3, you only get assault rifle reloading ease ONLY if you use 30rd magazines. Though I have never used a drum, reloading with the 100-rd drum is probably clumsy because:
    – you can’t throw the empty drum away (ordinarily)
    – so you have to store (time consuming as it is bulky) and carry the nearly 1kg empty drum with you – a weight penalty belt-feeds don’t have

    But using only 30rd magazines, the Ultimax Mk 8 is merely an IAR, not a SAW. Which makes it only slightly better than the rifles that the rest of the section is already carrying.