|Type / action
|gas operated,rotating bolt
|5.56x45mm / .223 Rem, also 6.8×43 mm Rem SPC
|3.26 kg / 7.2 lbs
|686 mm / 27" with 16"barrel
|406 mm/ 16", also 356 mm / 14" and 508 mm / 20"
|10, 20, 30 and 42 rounds
The STG-556 rifle was developed by US-based company Microtec Small Arms Research, a sister company to famous hi-tech knife-maker Microtec Knives Co. Based on the famous Austrian Steyr AUG assault rifle. Manufacture of this clone became possible because original patents for SteyrAUG have expired, and the demand for civilian version of this weapon in USA was not covered by import of original Austrian-made rifles. MSAR designers took some time to reverse-engineer the Steyr AUG,and then added several additional features that they feel might appeal to US shooters. Most notable of these new features are bolt stop release button and Ar-15 style bolt -closure forward assist button on the left side of receiver. Otherwise, the STG-556 follows the Steyr AUG A2 rifle pattern. Microtec MSARSTG-556 rifle is available in different colors and with barrels of various lengths. Optional caliber conversion kit allows to upgrade the rifle from 5.56mm / .223 to more potent 6.8mm Rem SPC caliber. SAR also offers STG-556 in either semi-automatic only (civilian / police) or selective-fire (military) versions.
Microtec MSARSTG-556 rifle is gas-operated semi-automatic or selective-fired weapon of bullpup configuration. The receiver is made from aluminum alloy, the stock / housing is made from impact-resistant polymer. Barrels are quick-detachable, with barrel lock incorporated into the gas block /forward grip base. Gas system features short-stroke gas piston, located to the right of the barrel. Bolt group rides on dual guide rods, and different user-replaceable multi-lug rotary bolts are available for right- or left-hand ejection. STG-556 is equipped with bolt hold-open device; bolt catch release button is located on the left side of the gun, behind the magazine housing. The M16 / Ar-15 type bolt closure assist button is located on the left side of the gun, in front of the magazine. Non-reciprocating charging handle is located also on the leftside, in front of the receiver. STG-556 accepts proprietary Steyr AUG-type magazines, made of plastic; magazine release button is located below the stock, behind the magazine housing. Manual safety is of cross-bolt button style, located above the pistol grip. In military select-fire version, mode of fire is controlled by the pull of the trigger – short pull results in single shots, long pull produces full automatic fire.STG-556 is offered either with Steyr AUG-type1.5X magnification telescope sight on special detachable mount, or with Picatinny rail (also on detachable base).