The Knights Armament rail adapter system (RIS) for the M249 squad automatic weapon (SAW). The rail bolts on the receiver with minimal difficulty and gives the end-user the ability to have rails on 3, 6, and 9 o’clock positions of the receiver. The rail will also work on the FN M249S semi-auto variant as well as the MK46 and MK48.
The KAC RAS weighs in at just a little over 5 ounces in total weight. Compared to the traditionally issued tri-rail that weighs over 12.5 ounces. Not only is the KAC rail lighter, but it also does not have as big of a footprint in terms of the width.