The Ultimax 100 Section Automatic Weapon[1] is a Singaporean light machine gun designed by Jim Sullivan and Bob Waterfield in 1980 and produced by Chartered Industries of Singapore (now ST Kinetics) since 1982. It is the standard light machine gun in use with the Singaporean Armed Forces.

History[edit | edit source]

Work on a new light support weapon for the Singapore Army started in 1978, with a team of engineers at CIS led by American designer L. James Sullivan. The weapon was first conceived in 1980.[2] The weapon entered initial service and production in 1982,[3] and is currently used by the Republic of Singapore Armed Forces and various other militaries as a squad automatic weapon.

Various iterations of the Ultimax 100 have been produced since the weapon's inception, with the latest, the Mk 8, being showcased in 2012 and 2019 under two different designs. It is currently touted by ST Kinetics as "the world's lightest machine gun".[4] The weapon was imported into the United States by American Defense Management, Inc. for a time, while marketing was done by Vision Technologies Systems (now known as ST Engineering North America).[5][6]

Overview[edit | edit source]

The Ultimax is a gas-operated light machine gun using a short stroke gas piston. The weapon features a locked breech with 7 locking lugs and fires from an open bolt. Early versions of the Ultimax can only fire fully automatically, while later iterations such as the Mk 8 are select-fire. The weapon is considered to be one of the lightest machine guns in the world.[7]

An unusual quirk about the Ultimax compared to other contemporary machine guns was that the weapon was intentionally designed to feed from magazines as opposed to belts. Early iterations of the weapon usually feed from a proprietary 100-round polymer drum magazine, but may also accept modified 20- or 30-round STANAG magazines. Starting from the Mk 4, the Ultimax can accept normal, unmodified STANAG magazines;[3] however, with the various modifications done to the magazine well, the Mk 4 Ultimax 100 cannot use Beta C-Mags or the proprietary 100-round drum magazines. This was rectified in the Mk 5 which can accept the Beta C-Mag.[3] The Mk 8 can accept STANAG magazines as well as the Beta C-Mag, as well as SAR 21 magazines; the Mk 8 can also accept the proprietary 100-round drum magazines of earlier versions of the weapon[4] through the use of a magazine well adapter.[8]

The weapon is striker-fired. The weapon's bolt contains both a spring extractor and a case ejector. The weapon's charging handle is located on the left of the weapon and does not reciprocate when firing. The weapon is also designed to mount a bayonet, although this is rarely, if ever, used in practice. The weapon may also mount optics. The weapon has a five-point adjustable gas valve, allowing the weapon to operate in a wide variety of conditions. The weapon is usually also fitted with a slotted flash hider. Early iterations of the weapon feature a foregrip, but later iterations have ditched this in favor of Picatinny rails which can be used to mount foregrips. The Ultimax is mainly made of an impact resistant polymer.[9]

A notable feature of the Ultimax 100 is its low recoil, achieved through the use of a "constant recoil" system; the overall design has the bolt carrier group travel all the way back without hitting the rear, while stopping gradually along the axis of movement against the resistance of the return springs.[10] The weapon's overall ergonomics are noted to be very similar to that of a Thompson submachine gun.[3] The rate of fire is said to be adjustable.[9]

Widespread adoption of the weapon may have been hampered by the weapon's proprietary drum magazine, however; the magazine is noted to be difficult to load without the use of a special loading mechanism, with the shape of the drum magazine noted as being large and bulky, occupying more space than that of an M16 magazine or even belt boxes for machine guns such as the M249. The Ultimax was also unable to take unmodified M16 magazines from squadmates, although modifications made by American Defense Management, Inc.[5] and later iterations of the Ultimax attempt to fix these issues.[8]

Variants[edit | edit source]

Mk 1

Pre-production variant with quick-change barrel.

Mk 2

Essentially Mk 1 without quick-change barrel.

Mk 3

Reintroduces quick-change barrel. Most ubiquitous version of the Ultimax and currently the version adopted by the Republic of Singapore Armed Forces.

Mk 3 Commando

Shorter-barrel version of the Mk 3 with removable stock. Intended for use by paratroopers.

Ultimax 2000

Precursor to the Mk 4. Essentially a Mk 3 with the ability to use STANAG magazines and features a folding wireframe stock.[11] Not offered for sale and remained a prototype.[5]

Mk 4

Developed for the United States Marine Corps Infantry Automatic Rifle program with wireframe folding stock and ability to take normal STANAG magazines. Developed in partnership with American Defense Management, Inc.[5] Features new fire selector module. Lost out to the M27 Infantry Automatic Rifle.

Mk 5

Updated variant of the Mark 4 with a folding stock, Picatinny rails and M16 STANAG 4179 magazine well that will accept 30-round box magazines and the 100-round Beta C-Mag drum.

Mk 8

Latest variation of the Ultimax 100 weapon system. Essentially a modernized Mk 5. Entered full production in 2018.[8] Can use STANAG magazines, SAR 21 magazines, Beta C-Mags and Ultimax drum magazines through the use of adapters.

Gallery[edit | edit source]

See Also[edit | edit source]

References[edit | edit source]

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