Country of origin

United States


Microtech Small Arms Research

Year(s) designed


Production began


Production ended


Weapon type

Semi-automatic rifle


5.56×45mm NATO
.300 AAC Blackout


Short stroke gas piston operated, rotating bolt

Overall length

26.5 inches (67 centimetres)
27.2 inches (69 centimetres)

Barrel length

18.5 inches (47 centimetres)
24 inches (61 centimetres)

Weight empty

7.2 pounds (3.3 kilograms)

Magazine/Cylinder capacity

30-round detachable box magazine

The MSAR STG-556 is a American semi-automatic rifle.


First revealed at the 2007 SHOT Show, the STG-556 was manufactured by a subsidiary of Microtech Knives, Microtech Small Arms Research. Little is known about the history of the weapon other than that.

Design DetailsEdit

Despite being regarded as a Steyr AUG A1 clone, the STG-556 is not truly a clone of the AUG due to some differences. One notable difference is that the STG-556 has the bolt release mechanism from an AR-15 located on the left side of the rifle. Another difference with older versions of the STG-556 is that its magazines are not STANAG-compliant; instead, it uses proprietary clear-sided magazines that resemble the ones used by the AUG. However, later versions of the STG-556 are able to accept STANAG magazines.


STG-556 Limited Edition

Limited edition run of the STG-556; this version is very much like the standard STG-556, except that it uses a Steyr AUG A3 body. 1000 weapons were made, all finished in black. 232 more were made with a 18.5 in (47 cm) barrel after it was discovered that the 18 inch barrel had better barrel harmonics than the standard full-length 24 in (61 cm) barrel.

STG-556 Gebirgsjäger

Limited edition run of the STG-556; this version is the exact same as the STG-556 Limited Edition except that all weapons had a drab green finish. 500 weapons were built.

See alsoEdit