STANAG magazine
The Infantry Automatic Rifle program began on 14 July 2005, when the Marine Corps sent Requests For Information to arms manufacturers. Characteristics desired in the weapon included: portability and maneuverability; similarity in appearance to other rifles in the squad, reducing the likelihood that the gunner will receive special attention from the enemy; facilitation of the gunner's participation in counter-insurgency operations and capability of maintaining a high volume of fire. An initial requirement for a magazine with a minimum capacity of 100 rounds was dropped in favor of the 30-round STANAG magazine because, at the start of testing, available 100-round magazines were unreliable. Caliber was specified as 5.56×45mm with non-linked ammunition, so as to achieve commonality with existing service rifles.