Ultimax 100 manual

The Ultimax 100 was designed in the late 1970s in Singapore as a lightweight squad automatic weapon. It’s a gas-operated design, with special attention paid to reducing felt recoil. The receiver is longer than most similar guns, and a carefully calibrated recoil spring prevents the bolt from contacting the back end of the receiver. We’ve not yet fired one, but by all accounts this translates the recoil impulse into a steady soft push instead of a series of impacts, and makes the weapon extremely controllable despite its light weight (under 11 pounds).

The Ultimax is also intentionally magazine-fed, instead of using belts. This was done to increase reload speed and allow more effective use by a single shooter (belt loading is usually a 2-man affair). Early variants of the Ultimax used proprietary drums, but the recent Mk IV is set up for standard AR magazines and Beta-C drums. By most accounts, the Ultimax is the premier light machine gun in existence today, and really makes the M249 SAW look clumsy. We can’t attest to that from experience, so instead we will leave you with a copy of an Ultimax Mk III technical manual (complete with exploded drawings):

(1984) Ultimax 100 MkIII manual (English)


  1. The manual is great !
    It has a quickly detachable barrel – a good feature. If it’s buffer system works well in all weather conditions and in intensive shooting, then it must be a pretty effective gun.
    I’ve shot Russian PKM belt fed machine gun and I was reloading it’s 250 round belt by myself (no need of an assistant) and it’s not so hard. Sure, it takes more time to load a belt fed gun, than a mag fed one, but if high capacity is needed, I’ll prefer a belt fed gun, because I don’t trust those hi-cap drum mags very much (from my experience , they fail much more often than the belt). Also belts are not so sensitive to dust and mud as drums are! Also you can have more ammo in a single belt (actually as much as you want or can carry). I like belts 🙂

    • The Ultimax’s drum is pretty well-designed, though somewhat large. I don’t disagree that, for now, belt-fed is the way to do GPMGs, but for what the Ultimax is primarily designed for, I don’t see the drums being a big issue. The AR-15 magazine acceptance system was a bit tenuous, though.

  2. I fired an Ultimax 100 at Knob Creek 2010, recoil is comparable to a full-auto .22. It is a well-built, exceptionally controllable, accurate gun. Scoring hits out to 500 yards was a piece of cake. A really exceptional design, if you ask me.

    • The videos you see of guys shooting the Ultimax off their nose are really no joke. It’s that controllable. I was surprised at the quality, too; the weapon is made of stamped components and injection molded plastics, but neither felt flimsy. Despite weighing only 10lbs, the stamped parts were made of thick (1.5mm or so, by my estimates) metal, and the plastics seemed equally solid to any modern polymer.

      My only complaint is that reloading via AR-15 magazines, while workable (I experienced no feed issues with the magazine I shot), is slow and somewhat clumsy.

  3. l james sullivan, designed ar 15 from ar 10 and stoner 63 from stoner 62… as well as many other things…

  4. I am a Class II SOT (i.e. licensed to manufacture machine guns) and own two Ultimax 100 dealer samples (Mk II and Mk III). Having shot and/or owned many subguns, full auto assault rifles, and light machine guns, I can tell you that the Ultimax 100 is my all time favorite to shoot. Everything you hear about the recoil is true (light, constant push). At 100 yard, I can easily put 80-90 rounds of a 100 round drum on a man sized target while doing a standing drum dump.

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