During 1970s Singapore Army used US-designed M16A1 assault rifles. In 1976, a company called CIS (Charter Industries of Singapore, now ST Kinetics), began to develop its own assault rifle with aim to supply these rifles for Singapore military and for foreign countries. To save the time CIS invited some engineers from British company Sterling Armament, who used to manufacture US-designed Armalite AR-18 assault rifle, so new Singapore rifle heavily borrowed from original AR-18 design. First prototypes came out in 1978 and the final design was approved by Singapore military in 1984 under the name of SAR-80. This rifle was used to some extent by Singapore Army and also was exported to some countries, including Croatia.
SAR-80 is a gas operated, selective fire weapon of simple construction. It uses short stroke gas piston that pushes the massive bolt carrier with rotating bolt. The bolt carrier rides on two guide rods. Each rod has a recoil spring around it, gas piston rod has its own return spring. The receiver is made from steel stampings. Pistol grip, hand guards and buttstock are made from plastic. SAR-80 uses M16-style magazines. Gas drive has gas regulator that can be cut off completely to safely launch rifle grenades from the muzzle.