The Ultimax 100 MKII LMG - 'The lightest 5.56mm Light Machine Gun in the world'

I purchased the above Ultimax LMG at the Birmingham Arms Fair last weekend. I have thought about getting one for some time and the price was right at the time. People seem to have quite mixed feelings about this weapon. Despite the fact that I have heard it referred to to as a crapymax, much of the textual information from the 'experts' would suggest quite the opposite.

The Ultimax 100 is a magazine-fed, gas piston-operated, rotating bolt, air-cooled light machine gun. It is a one-man weapon and can be fired from the shoulder, hip or a bipod. The Ultimax 100 was designed to meet the basic requirements expected for any Squad Automatic Weapon (SAW), i.e. to provide controlled and sustained fire and yet to be light weight. The Ultimax 100 had since, established itself as the lightest Light Machine Gun in the world to-date and has been adopted by many users world wide. It is or rather was made by the Chartered Industries of Singapore (CIS). It is a rugged and durable design with high firepower and easy handling. It can use 60 or 100 round drum magazines or the same 20 or 30 round box magazines that are used in the SAR80 assault rifle. A pack holding four 100 round drums is available. The gas system has a regulator to increase power when operating in adverse conditions (or to cut gas flow off to launch rifle grenades). The barrel has a bayonet (M7) lug and the Ultimax can also launch rifle grenades. The folding bipod is attached to the front of the receiver assembly. In the MKIII version there is also a short 12" barrel which, when the removable buttstock is taken off, gives a very short and handy LMG. The Ultimax 100 is very controllable (even for lightly-build people) on full automatic fire.  It is used by Singapore armed forces (Singapore Guards) and U.S. Navy (SEALS).

The MKII version of the Ultimax
is no longer produced and has been superseded by the MKIII version. This has a quick change barrel, a few minor cosmetic changes and a different finish (black enamel or similar). MKIII versions are very rare in this country (deactivated). Even rarer, however, are the 100 round drum magazines for the Ultimax. Although CIS or STKinetics as it is now known seems happy enough to export the weapons to the UK, they don't seem to want to let the drum magazines into the UK. If you find one, you can expect to pay as much as (if not more than) you paid for the weapon itself!

The review weapon has about 85% of its finish remaining. Overall, it is in good condition, although the gas regulator has been forced and jammed at some point. One of the things you do notice when you pick up the Ultimax is its weight, or rather lack of it. It really is very light; it is also comfortable to shoulder and aim. The foregrip appears to be quite small, but it doesn't really feel that way when you are grasping it.

The bipod is simple but highly effective. To bring it into operation you simply pull lightly on each leg and swing it into the down position. Height adjustment is achieved through a simple button catch on each leg - once again, this is very easy to operate.

The Ultimax has a flash eliminator very similar to the M16 version and it does take the standard US M7 bayonet (M16). It will also take an M16 sling or indeed most other types of military sling. 



One of the most interesting aspects about this LMG is that it has been designed to allow removal of the rear stock. This then gives a much shorter weapon which is even more handy for use in and around vehicles or by airborne troops. The Ultimax uses a  "Constant Recoil" concept to give exceptional controllability in automatic fire, better than any existing assault rifle, and other light machine guns. The "Constant Recoil" concept involves a relatively long travel for the bolt carrier so that it does not come into contact with the rear end of the receiver. In addition, the Ultimax 100 is designed such that the impulses generated from the bolt action cancel one another during each operating cycle, resulting in smoother recoil action. Accuracy in automatic fire depends on a weapon's controllability. The minimal recoil of the Ultimax 100 enables it to be fired accurately in full automation under control from the hip, even with only one arm. The controllability of the Ultimax 100 is also not affected when it is fired with the butt detached.

The charging handle used to cock the mechanism is a little unusual in that it requires the user to rotate it before it can be moved to the rear. It is then held at the rear until the trigger is pulled, i.e. it fires from an open bolt. As long as the trigger remains back, the bolt will cycle. The fire selector lever on the Ultimax is basic having only two positions; safe and full auto - see photo left (selector above trigger can be rotated down (safe).






The RHS side of the receiver has the ejection port which has an M16 style flip-up cover. Also on the RHS is the magazine release button. This can be a little confusing as its shape suggests that it should be turned (from the bottom) rather than pressed. The carrying handle is effective, but gives the appearance of being quite flimsy. The lack of ability to fold down is a disadvantage, but one which was recognised and dealt with in the MKIII version.

The photo below shows a view into the receiver with the bolt assembly removed. You can just about see the cut outs in the chamber for the locking lugs on the bolt head. The U shaped object in the foreground of the picture is the top of the trigger assembly - it lowers when the trigger is pulled.

The Ultimax has a simple peep sight which converts into a long range sight when it is flipped up. See photo below

Other views.

Stripping the weapon is easy. Follow the steps shown below:

In summary, I think that the Ultimax represents excellent value for money. A deactivated Ultimax 100 MKII retails for about 295 give or take. When you think that you are getting a modern LMG that to be honest is more like an assault rifle (particularly in its proportions), then you are getting plenty for your money. If you want an Ultimax, then they are available from World Wide Arms (01785 851515) as are the M7 bayonets.

If you want to see what the latest Ultimax looks like then download this flyer. You will need Adobe Acrobat Reader to view it.







5.56 x 45 mm




472 mm



Overall with buttstock

1024 mm


Overall without buttstock

810 mm


Barrel (standard)

508 mm



Gun bare with bipod

4.9 kg


With bipod and empty 100-round drum magazine

5.5 kg


100-round magazine empty

0.6 kg


100-round magazine loaded



Combat ready with bipod, sling and fully loaded 100-round magazine

6.8 kg



For M193-type ammunition

6 grooves, right-hand twist, 1 turn in 305 mm


For NATO-type ammunition

6 grooves, right-hand twist, 1 turn in 178 mm




Rate of Fire


400 600 rpm


Muzzle Velocity

For M193-type ammunition

970 m/sec


For NATO-type ammunition

945 m/sec


Maximum Effective Range

For M193-type ammunition

460 m


For NATO-type ammunition

1,300 m