XM312

Reality
The XM312 is a heavy machine gun derived from the XM307 25mm grenade autocannon and chambered for the .50 BMG cartridge. It was designed in response to a request by the U.S. military for a replacement for the aging M2HB heavy machine gun, and as a complement to the heavier XM307. It is capable of being converted quickly into an XM307 with a small number of parts and a few minutes of work at the unit level (and vice versa from the XM307)[1]. Procurement of the XM312 will allow easier use of the XM307, as only the related kits would have to be adopted.[1] In 2005 field testing began with the XM312, but the test results were not encouraging because of the very low rate of fire of only 260 rounds per minute, so it initially seemed unlikely the XM312 would have ever entered service with the U.S. military.[2][3] However, on May 20th 2008, Jane's Information Group reported that the U.S. Army has awarded GDATP (General Dynamics Armament and Technical Products) a 9 million dollar contract to develop a lightweight 0.50-calibre machine gun called the LW50MG to replace the Browning M2, starting deployment in 2012.[2]. The Army at present will buy new M2s and Mk 19s to replace the current guns that are wearing out.

Battlefield: Bad Company 2
In the game, the XM312 is a usable mounted/stationary weapon. The XM312 is also mounted on the HMMWV 4WD as the vehicle's main turret.