[IDEX 2019] Steyr AUG .300 BLK and STM556 from Austria

    Steyr Mannlicher attended IDEX with a somehow low profile booth in the Austrian pavilion. In the small space, they managed, however, to showcase a good selection of their products, from the new A2 pistol in different configurations to the impressive HS50 anti-materiel rifle.

    The two most interesting products were, however, an “Americanized” Austrian bullpup and an “Austrianized” American assault rifle. Let’s have a quick look at them.

    Steyr AUG .300 BLK

    The AUG is a very well known platform, however, for those needing a brief and entertaining recap on its features, James’ recent video review will be helpful. Therefore we can focus only on the details where this model differs from current production.

    Indeed, besides the obvious caliber change, differences are quite subtle. The main one is probably the implementation of the bolt release in a stock accepting STANAG style magazines. Previously, the AUG could be had with stock using its proprietary “waffle” magazines and bolt release button, or with stock accepting STANAG mags and no bolt release. The latter is the one that can be seen in James’ video.

    Another couple of points pointed out by Steyr representative were the long Picatinny rail and the QD attachment point on the left side of the rail. The main feature of the rail is that it rides over the stock with a rigid “upside down U” shape. This allows it to ride over the little lip which can be found on top of some versions of the stock, right above the handle.

    Steyr AUG .300 BLK; QD barrel changing system is unmodified.

    The main feature: the bolt release button just above the PMAG style magazine.

    Steyr STM556

    Since the AUG is great but the world prefers the AR-15, Steyr designers in 2012 offered their take on the American design.

    In short, the STM556 is a short-stroke piston operated AR-15 with a quick barrel changing system directly inherited from the AUG. This rifle was also the starting point for the RS556 which Steyr and Rheinmetall jointly submitted to the tender to replace the rifle of the German Army.

    Suppressed Steyr STM556.

    Steyr STM556, note the rail extending over the adjustable gas block.

    Steyr STM556: closeup of the adjustable gas block and quick barrel changing system reminiscent of the AUG.

    Closeup view of the Steyr suppressor.

    Giorgio O

    Italian firearm enthusiast now living in an even more restrictive country, Giorgio has a passion for innovative or plainly unusual mechanical solutions. He’s also interested in manufacturing technologies with a recent focus on additive manufacturing.

    You can contact him at giorgio_o at zoho dot com and you’ll find him in the comments section as Giolli Joker.