I thought that the Army was going to do away with the direct impingment system and go to a piston operated system on the M4 carbines?
http://www.thetacticalwire.com/story/258857
April 26 : 2012
US Army Awards M4 / M4A1 Carbine Contract to Remington® Arms
http://www.thetacticalwire.com/story/258857
April 26 : 2012
US Army Awards M4 / M4A1 Carbine Contract to Remington® Arms