Ultimax 100

Ultimax 100
A Singaporean soldier with a deployed Ultimax 100 Mk 2 Section Assault Weapon (SAW)
Type	Light machine gun
Place of origin	Singapore
Service history
In service	1982–present
Used by	See Users
Wars	Bougainville Civil War Yugoslav Wars Anti-guerrilla operations in Indonesia & Philippines 2006 Fijian coup d'état Solomon Islands coup Afghanistan war Sri Lankan Civil War
Production history
Designer	L. James Sullivan for Chartered Industries of Singapore (CIS, now ST Kinetics)
Designed	1977
Manufacturer	• CIS: 1982–2000 • ST Kinetics: 2000–present
Produced	1982–present
No. built	~80,000
Variants	See variants
Specifications
Weight	• Mark 2: 4.75 kg (10.47 lb) • Mark 3: 4.90 kg (10.8 lb)
Length	• Mark 2: 1,030 mm (40.6 in) with buttstock, 800 mm (31.5 in) w/o buttstock • Mark 3: 1,024 mm (40.3 in) with buttstock, 810 mm (31.9 in) w/o buttstock
Barrel length	• Standard: 508 mm (20.0 in) • Ultimax 100 para: 330 mm (13.0 in)
Cartridge	5.56×45mm NATO
Caliber	5.56 mm (0.22 in)
Barrels	Single barrel (progressive RH parabolic twist, 6 grooves)
Action	Gas-operated, rotating bolt
Rate of fire	400–600 rounds/min
Muzzle velocity	970 m/s (3,182 ft/s) (M193 cartridge) 945 m/s (3,100.4 ft/s) (SS109/M855 cartridge)
Effective firing range	100–1,200 m sight adjustments
Maximum firing range	460 m (M193 cartridge) 1,300 m (SS109/M855 cartridge)
Feed system	100-round drum magazine or 30-round STANAG M16 box magazine
Sights	Rear aperture sight and front post 472 mm (18.6 in) sight radius

The Ultimax 100 is a Singapore-made 5.56mm light machine gun, developed by the Chartered Industries of Singapore (CIS, now ST Kinetics) by a team of engineers under the guidance of American firearms designer L. James Sullivan. The weapon is extremely accurate due to its constant-recoil operating system. It is considered one of the most lightweight machine guns in the world.

Work on a new light support weapon for the Singapore Army began in 1978. The weapon is produced by CIS (presently STK—Singapore Technologies Kinetics), initially in the Mark 1 version, later—the Mark 2, and currently, in the Mark 3 and Mark 4 variant. The Ultimax 100 (also called the U 100) is used in significant numbers by the armed forces of Singapore, Croatia and the Philippines. The Mark 3 variant is currently used in the Singapore Armed Forces primarily as a support arm, and is both classified and known by soldiers as the SAW (Section Assault Weapon).

The Ultimax 100 is a gas-operated automatic weapon (capable of fully automatic fire only) with a short-stroke gas piston operating system powered by ignited powder gases diverted from the barrel through a port in the gas block. The Ultimax 100 is a locked breech weapon with a rotating bolt that contains 7 locking lugs. It fires from an open bolt position. The bolt contains both a spring extractor and a casing ejector. The weapon's non-reciprocating cocking handle is located on the left side of the receiver and occupies the forward position during firing. The Ultimax 100 is striker-fired.

The feature that grants the weapon its low recoil (compared to similar light machine guns) is the "constant recoil" principle. The overall design allows the bolt carrier group to travel all the way back without ever impacting the rear, instead stopping gradually along the axis of movement against the resistance of the return springs.Jane's International Defence Review correspondent — Andrew Tillman, in an exclusive invitation from ST Kinetics to participate in the Product Improvement Program (PIP, initiated in 1989) to test fire the gun, elaborated: