The Marine Corps wants a 30 percent weight savings over existing linked belts of .50 caliber ammo.
Marines Seek to Order 2.4 Million Polymer-Cased .50 Cal Rounds (VIDEO)
M2 Browning, Vietnam War
Unsung: The AN/M2 .50-cal. Machine Gun in World War II
The U.S. Army's Quest For a Lethal New .50 Machine Gun
Machine Guns
The United States Army, Fort Moore, Photo Essay
Military Gun Mounts & Machine Gun Tripod Mounts
Ammunition
DVIDS - News - Polymer ammo: A lightweight approach to support the warfighter
Army, Marines Want New Machine Guns to Replace the M240 and 'Ma Deuce
MARSOC to evaluate machine gun that could replace both the M240 and .50 caliber 'Ma Deuce
This move could shave 20 pounds off a belt of .50-cal ammo
New Weapon on the Battlefield: .338 Machine Gun – Small Arms Defense Journal
The Military Small Arms & Other Weapons discussion thread, Page 6
M2 50 caliber heavy machine gun hi-res stock photography and images - Page 3 - Alamy