Ultimax 100
ST Kinetics · Machine Gun · In Production · 1982
Also known as: U100, CIS Ultimax 100
Overview
The Ultimax 100 is a Singaporean 5.56x45mm NATO light machine gun designed by American firearms engineer L. James Sullivan for Chartered Industries of Singapore (now ST Engineering Land Systems). A gas-operated, rotating-bolt weapon firing from an open bolt, it is renowned for its 'constant recoil' system, in which the bolt group never strikes the rear of the receiver, producing exceptionally low felt recoil for its class. Lightweight at roughly 4.75 kg, it feeds from 100-round drum magazines or standard box magazines and has equipped the Singapore Armed Forces as a squad automatic weapon since the early 1980s.
Specifications
| Weight (empty) | 4750 g (167.6 oz) |
| Weight (loaded) | 6800 g (239.9 oz) |
| Overall Length | 1030 mm (40.55") |
| Folded Length | 800 mm (31.50") |
| Barrel Length | 508 mm (20.00") |
| Action Type | Gas Operated |
| Firing Mechanism | Open Bolt |
| Magazine Capacity | 100 rounds |
| Magazine Type | Drum |
| Muzzle Velocity | 970 m/s (3182 fps) |
| Effective Range | 460 m (503 yd) |
| Maximum Range | 1000 m (1094 yd) |
| Rate of Fire | 500 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Steel |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 5.56x45mm NATO · primary · 5.56x45mm NATO — also known as 5.56mm NATO, 5.56x45mm, .223 Remington
Features
- Firing modes: Full Automatic
- Feed systems: Detachable Box Magazine, Drum Magazine
- Safety mechanisms: Manual Safety
- Features: Constant Recoil System, Quick Change Barrel, Rotating Bolt, Bipod, Removable Buttstock
Variants
- Ultimax 100 Mk 3 — Quick Change Barrel
- Ultimax 100 Mk 5 — Modernized
- Ultimax 100 Mk 8 — Modernized
Service history
Operators
- Singapore Armed Forces · adopted 1982
- Armed Forces of the Philippines
- Croatian Armed Forces
- Indonesian National Armed Forces
Conflicts
- Insurgency in the Philippines (1969-present)
Production
Estimated total produced: 80,000 · Production years: 1982-present
Approximately 80,000 units produced; successive Mark variants (Mk 1 through Mk 9) have modernized the design
Origin
Country of origin: Singapore
Designer: L. James Sullivan
Notes
The constant-recoil principle makes the Ultimax 100 one of the most controllable light machine guns in full automatic fire, allowing it to be fired accurately from the shoulder or even one-handed.
Background
Designer L. James Sullivan had earlier worked alongside Eugene Stoner on the AR-15 and the Stoner 63 weapon system, and applied his obsession with recoil mitigation to the Ultimax 100, engineering a bolt that travels its full stroke without ever bottoming out against the receiver.