The M85 is a
heavy machine gun
A heavy machine gun (HMG) is significantly larger than light machine gun, light, medium machine gun, medium or general-purpose machine guns. HMGs are typically too heavy to be man-portable (carried by one person) and require weapon mount, mountin ...
firing
.50 BMG ammunition that was used primarily for turreted applications in
armored fighting vehicle
An armoured fighting vehicle (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can be wheeled or tracked. Examples of AFVs are tanks, armoured cars, ...
s. It was intended to replace the venerable
M2 machine gun
The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed towards the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, wh ...
with a smaller and much lighter weapon, suitable for use inside fighting vehicles, as opposed to only on external mounts. It was used on the
M60 series of tanks and the
LVTP-7 amphibious landing vehicle.
Design and development
Intended as a smaller, lighter, more capable replacement for the venerable
M2 Browning machine gun
The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed towards the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, w ...
, the M85 was produced by
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
. The weapon was developed with selectable high and low rates of fire for engagement of both ground and air targets, a feature lacking in the older M2.
The M85 was the standard heavy tank machine gun for the M60 series, and was also used on the LVTP-7 amphibious vehicle. It is an air-cooled, recoil operated machine gun, has a short receiver and quick change
barrel
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...
, and can be configured for left or right hand feeding. The M85 is significantly lighter than the M2 by 20lbs, and significantly smaller, a prime consideration for its intended role inside the cramped interiors of armored vehicles. Firing and charging are achieved by pull on one of two color-coded
pull chain
A pullstring (pull string, pull-string), pullcord (pull cord, pull-cord), or pullchain (pull-chain, pull chain) is a string, cord, or chain wound on a spring-loaded spindle that engages a mechanism when it is pulled. It is most commonly us ...
s (black for charging and red for firing), or firing could be initiated by means of a switch activated
solenoid
upright=1.20, An illustration of a solenoid
upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines
A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ...
on the M-19 cupola elevation mechanism.
The M85 used the M15 push-through link to feed ammunition as opposed to the M2 or M9 pull-out links used on the M2 and M3 Browning machine guns. The M85 had a slow (400rpm) & high (1100rpm) rate of fire. The link difference created issues with ammunition supply, since despite the same .50 BMG cartridges being used in both machine guns, the ammunition was supplied already packed on links. Re-linking was not practical in the field.
In service the M85 was found to be unreliable due to the metallic link catching in the feed system, compared to the stock M2 machine gun. The weapon was tested on the XM-1 Abrams, but not fitted to the production
M1 Abrams
The M1 Abrams is a third-generation American main battle tank designed by Chrysler Defense (now General Dynamics Land Systems) and named for General Creighton Abrams. Conceived for modern armored ground warfare and now one of the heaviest ta ...
, and was replaced by the M2 machine gun on the improved
AAVP-7. An attempt was also made to make a version of the M85 that would replace the M2 in the infantry role was designated the M85C, and features standard spade grips and can be fitted to the M3 heavy tripod. The M85C was unpopular and this weapon was not adopted.
The M85 was also tested by the United Kingdom under the designations XL17E1 and XL17E2. They were equipped with special purpose barrels and evaluated as ranging machine guns.
[Ezell, 1988. p. 391] The weapon was not adopted for use on any British vehicles.
Variants
M85
*Basic weapon, designed for mounting inside vehicle cupolas
M85C
*Flexible infantry variant with sights and spade grips
See also
*
M2 Browning machine gun
The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed towards the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, w ...
References
;Notes
;Bibliography
*Ezell, Ed. ''Small Arms Today, 2nd Edition.'' Harrisburg, PA: Stackpole Books, 1988. .
*Gervasi, Tom. ''Arsenal of Democracy III: America's War Machine, the Pursuit of Global Dominance''. New York, NY: Grove Press, Inc, 1984. .
*Hunnicutt, R. P. "Patton: A History of the American Main Battle Tank." 1984, Volume 1; .
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External links
TACOM-RI Historic US Small ArmsOPEVAL prototype M85 (U.S. Army photo)M85 at Modern Firearms website
.50 BMG machine guns
Cold War firearms of the United States
Machine guns of the United States
Vehicle weapons