From the Gun Owners Resource OnLine Encyclopedia

XM312 Type Heavy machine gun Country of Origin USA Specifications Length 61.42 in. (1,560 mm) Weight 52 lb. (19kg) Width 9.84 in. (250 mm) Height 7 in. (180 mm), 18 in. (460 mm) adjustable tripod Cartridge .50 BMG Caliber 12.7mm action "Recoil-reducing action" (a modified rotating bolt) Rate of fire 260rpm Effective range lethal and suppressive to 2000 meters Feed belt fed Sights Open, optics may be mounted Production History Designer General Dynamics/Joint Services Small Arms Program Designed 2000 Manufacturer General Dynamics Production dates 2004 Number built Designed for a 2-man crew. Variants XM307

The XM312 is a heavy machine gun derived from the XM307 25 mm 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)[2]. Procurement of the XM312 would 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 pitifully low rate of fire of only 260 rounds per minute, so it is extremely unlikely the XM312 will ever enter service with the U.S. military.[3][4] (Interestingly enough, the newly designed XM806 is only rated to 250 rounds per minute as well.^[2]) 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 50-calibre machine gun called the LW50MG to replace the Browning M2, starting deployment in 2012.^[3]. The Army at present will buy new M2s and Mk 19s to replace the current guns that are wearing out.[5]

Contents 1 Specifications 2 Program status 3 References 4 External links

[edit] Specifications

• Weight:
  • 40 pounds (20 kg) max. (weapon only).^[4]
  • 40 pounds (20 kg) max. (ground mount system).
• Dimensions: 9.9W × 7.2H × 61.5L max. inches (25.1 mm × 18.3 mm × 1562 mm) (52.5L, 1334 mm) charged).
• Portability: Man portable or vehicle mountable.
• Stability: Up to 18 inch (460 mm) tripod height.
• Operation: Currently a hybrid gas & recoil operating group. Gas powers the bolt mechanism while recoil drives the barrel/barrel extension and the feed system. Design changes are underway to totally eliminate the gas system to provide increased reliability and reduced complexity.
• Environmental: Operationally insensitive to conditions.
• Reliability: 6,000 MRBF (threshold) / 10,000 MRBF (objective).
• Rate of fire:
  • 260 rounds per minute (4.3 Hz)(cyclic).^[5]
  • 40 rounds per minute (0.7 Hz) (sustained, without barrel change). In burst of five to seven rounds, the same as the M2HB.
• Dispersion: Less than 1.1 milliradian, one sigma radius.
• Range: Lethal and suppressive out to 2,000 meters.
• Ammunition: .50 BMG M33 ball, M8, M20 & Mk211 API, M903 SLAP.
• Recoil: 300 foot-pounds (407 J) (similar to the 7.62 mm M240).^[4]
• Feed system: Weapon-mountable ammunition can or feed from any can using bellmouth attachment. M9 rear stripping link—common with current M2 ammunition. Left hand feed, right hand eject of cases and links.

[edit] Program status

• September 2005: The XM312 is test fired by troops from the 1st Infantry Division at the Grafenwöhr Training Area in Germany.^[6]

[edit] References

[edit] External links

• General Dynamics 12.7mm / .50 XM312 Machinegun (USA) - Modern Firearms
• XM312 - Deagel