In the 1990s, PT Pindad locally produced the Belgian Fabrique Nationale FN FNC under license as the "SS1". This eventually gave birth to the improved and updated SS2 series of 2006. The SS3 has since become "bullpup" version of this very same assault rifle and is currently undergoing late-stage development for possible use by Indonesian forces. The "SS4" is another PT Pindad product though intended for use as a dedicated "Battle Rifle" to suit the needs of the Indonesian military and possible export suitors.
The Battle Rifle is a specially categorized military firearm that is separate from the traditional "assault rifle". It is generally an automatic rifle (self-loading) system though chambered to fire a full-power rifle caliber cartridge instead of the largely-accepted assault rifle cartridge forms currently available. Battle Rifles allow for the engagement of targets beyond the range of traditional assault rifles though this often makes them cumbersome to wield, particularly under full-automatic fire. Perhaps one of the best examples of this rifle type is the Belgian Fabrique Nationale FN FAL utilized the world over since 1947.
The SS4 will be chambered for the 7.62x51mm NATO standard rifle cartridge. As in the SS1, SS2 and SS3 prior, the SS4 will also make use of the familiar gas-operated, rotating bolt firing function. The weapon will feed from a 15-round detachable box magazine and sport an adjustable stock for improved ergonomic comfort. Adjustable iron sights will be standard fittings though the use of optics will be present, broadening the tactical usefulness of the SS4.
The "SS4" designation stems from the "Senapan Serbu 4" terminology, translating simply to mean "Assault Rifle 4", and falls in line with the naming convention utilized in the prior SS1, SS2 and SS3 series firearms.