Has Steyr combined the AUG and the AR to create the ultimate combat rifle? Well, Steyr has been producing military rifles for 150 years, and the AUG gas piston system has been proven in use with numerous armies for several decades now. So adapting an AUG gas system and barrel into an AR-compatible upper receiver assembly can’t have been too much of a challenge for the company…

In fact, Steyr has received various requests from governments that had fielded AUGs and wanted the same performance from a less-conspicuous design. They wanted AUG performance with a rifle that looked like everybody else’s ARs. And then a couple of years ago the German army put out a request for rifles to replace its G36 rifles. Steyr Mannlicher joined forces with Rheinmetall and developed the STM-556 as their submission for this competition.

Read more over at Tactical-Life.com