From The Manufacturer/Wikipedia/People Smarter Than Us:
The new A10A4 carbine is both rugged and flexible. It is perfectly suited to both military and law enforcement duty. It is a gas operated, magazine fed, semi-automatic produced to provide a level of accuracy, dependability and durability that is not found in other rifles of similar design. The A10A4 provides a perfect platform for all sighting options with its forged flat-top receiver, MIL-STD 1913 rail and forward assist.