Machine guns introduction
Austria
 Schwarzlose M07 M07/12
 Steyr-Solothurn MG 30
 Steyr AUG /Hbar
Belgium
 FN Model D
 FN Minimi
 FN MAG
 FN BRG-15
China, People's Republic
 Type 67 GPMG
 Type 88 GPMG
 Type 95 LMG
 Type 77 HMG
 Type 85 HMG
 W-85 HMG
 Type 89 HMG
 Type 02 / QJG 02 HMG
Czech Republic
 ZB 26
 ZB 53 / Vz.37
 ZB 60 new
 Vz.52, Vz.52/57 upd
 UK Vz.59 upd
Denmark
 Madsen LMG
 Madsen-Saetter
Finland
 L/S-26
 Valmet KvKK 62
France
 Chauchat CSRG M1915
 Hotchkiss Portative
 Hotchkiss M1914
 Hotchkiss M1922 LMG
 Hotchkiss M1930 HMG
 MAC M1924/29
 AAT Mod.52
Germany
 MG 08, MG 08/15, MG 08/18
 MG 13
 MG 34
 MG 35/36 Knorr-Bremse
 MG 42 and MG 3
 HK 21 and 23
 HK MG 4
Great Britain
 Vickers Mk.I
 Hotchkiss Portable Mk.I
 Lewis
 Vickers-Berthier
 Bren
 L86A1 SA-80 LSW
Israel
 Dror
 Negev
Italy
 Fiat-Revelli M1914 M1935
 Breda M1930
 Breda M1937
Japan
 Type 03 & Type 92
 Type 11
 Type 96 & Type 99
 Type 62
Mexico
 Mendoza
Russia / USSR
 Maxim M1910/30
 Degtyarov DP DPM RP-46
 Degtyarov DS-39
 Degtyarov RPD
 Kalashnikov RPK
 Kalashnikov RPK-74
 Gorjunov SG-43 SGM
 Kalashnikov PK / PKM
 Pecheneg
 DShK DShKM 12.7
 NSV 12.7 'Utes'
 Kord 12.7
 KPV 14.5
Singapore
 STK Ultimax 100
 CIS .50 MG
South Africa
 Vector SS-77 / Mini-SS
South Korea
 Daewoo K3
Spain
 CETME Ameli
Sweden
 Knorr-Bremse m/40
Switzerland
 W+F Lmg 25
 SIG KE-7
 Steyr-Solothurn MG 30
 SIG MG 50
 W+F MG 51
 SIG MG 710
USA
 Benet-Mercie M1909
 Lewis
 Browning M1917 M1919
 Browning M1918 BAR
 Johnson M1941 M1944
 M60
 M16 LSW / LMG
 M134 Minigun
 XM214 Microgun
 Stoner 63
 M249 SAW
 M240
 Mk.48 mod.0
 Browning M2HB .50 cal
 XM312 .50 cal
 LW50MG

 Gatling, Minigun, Vulcan

all texts and some pictures
copyright © 1999-2009
by Max R. Popenker
and can not be used without author permission

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General Dynamics 12.7mm / .50 XM312 Machinegun (USA)

Caliber: 12.7x99mm (.50 Browning Machine Gun)
Weight: 19 kg on tripod
Length: no data
Length of barrel: no data
Feeding: belt
Rate of fire: 260 rounds/min

The original plans to replace obsolete, but numerous .50 caliber (12.7mm) Browning M2HB heavy machine guns in the US service listed the 25mm Xm307 OCSW weapon as a successor to the 80+ years old Browning. But the present delays in the development of the highly expensive and sophisticated OCSW led to the conclusion that the US Forces do need something new, and at least as effective as old "Ma Deuce" (M2HB) right now. So in 2000 US military requested for the lightweight, .50 caliber machine gun to supplement old M2HB until the arrival of the much more effective 25mm XM307 OCSW system, which will be capable of firing 25mm explosive shells with great accuracy and lethality. The described version of the XM312 "lightweight heavy machine gun" (sounds weird, huh?) is being developed by the General Dynamics, a huge US-based defense company. The XM312 is based on the 25mm XM307, but without its comprehensive and expensive explosive ammo and fire control it is much cheaper and could be finalized much faster. It is entirely possible that XM312 will enter limited service with US military before 2005, while XM307 OCSW is scheduled for much later date.

The XM312 will be one of the lightest (if not lightest of all) .50 caliber (12.7mm) machine guns on the market. This advantage, which will made it two-men portable, comes at the cost of decreased cyclic rate of fire, which is more than 2 times lower, than on other .50 caliber guns. This will made this gun strictly anti-ground weapon, because this low rate of fire will made it ineffective against fast-moving targets like helicopters and low-flying aircrafts. The practical rate of fire, however, is quoted to be no less than of M2HB, around 40 rounds per minute. XM312 also should be no less (if not more) accurate than the M2HB.

Technical description.
The design of the XM312 is based on the recoil-reducing action, developed for 25mm XM307 OCSW. The barrel is locked by the conventional rotating bolt, which is operated by more or less conventional gas system. The bolt group mover within the barrel extension, which, along with the barrel and gas system, can recoil inside the gun housing. The XM312 fires from the open bolt, and at the moment of fire the recoiling group (barrel, barrel extension, gas system and gas drive) is in its rearmost position. When gun is fired, special spring first begin to move recoiling group forward. Then, bolt is released, it strips the cartridge into the barrel, locks it and cartridge is fired, while recoiling group is still on the move forward. So, the recoil of the shot first had to overcome the inertia of the recoiling group, and only then group began to recoil back, compressing the return spring. At the same time gas drive unlocks the bolt, and retracts it within the barrel extension, extracting and ejecting a fired case. This somewhat complicated design results in significantly reduced recoil, and in conjunction with muzzle brake, in lightweight, but stable construction. The price of this reduction in recoil is complicated (and expensive) construction and low cyclic rate of fire. The feed is using same old metallic belts, and XM312 can be fed from either side, alternatively.

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