M60 machine gun
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| Caliber: | 7.62 × 51 mm NATO | |
| Firearm action: | Gas-operated, open bolt | |
| Barrel length: | 560 mm (22 in) | |
| Overall length: | 1,077 mm (42.4 in) | |
| Effective range: | 1,100 m (1,202 yd) | |
| Maximum range: | 3,725 m (4,075 yd) | |
| Cyclic rate of fire: | ± 550 round/min | |
| Sustained ROF: | 100 round/min | |
| Muzzle velocity: | 853 m/s (2,800 ft/s) | |
| Weight, unloaded: | 23.1 lb (10.5 kg) | |
| Manufacturer: | Saco Defense, U.S. Ordnance | |
The M60 machine gun (also seen M-60, formally Machine Gun, 7.62mm, M60) is a family of American machine guns, firing the 7.62 x 51 mm NATO cartridge. In the U.S. military, it has largely been replaced by various versions of the M240 machine gun. However, it remains in use in every branch, as well as some other countries (another major user was Australia); it continues to be manufactured into the 21st century.
The M60 can be used in both offensive and defensive configurations. In the offense, it provides a higher rate of fire, greater effective range, and uses a larger caliber-round than the standard-issue United States assault rifle, the M16. In defensive use, the long range, close defensive, and final protective fires delivered by the M60 form an integral part of an unit's battle plan.
The M60 is effective up to 1,100 meters when firing at an area target and mounted on a tripod, up to 800 meters when firing at an area target using the integral bipod, up to 600 meters when firing at a point target, and up to 200 meters when firing at a moving point target. U.S. Marine Corps doctrine holds that the M60 and other weapons in its class are capable of suppressive fire on area targets out to 1,500 meters if the gunner is sufficiently skilled.
The M60 is generally used as "crew-served weapon", which means that it is usually operated by more than one soldier, in this case two — the gunner and an assistant. The gunner carries the weapon while the assistant carries a spare barrel and extra ammunition in linked belts. The basic ammunition load carried by the crew is 600 to 900 rounds, which at the maximum rate of fire allows for approximately two minutes of continuous firing. In many U.S. units that used the M60 as a squad automatic weapon in Vietnam, every soldier in the rifle squad would carry at least 200 linked rounds of ammunition for the M60, a spare barrel, or both, in addition to his own weapon and equipment.
The designation is normally written without dashes (e.g. M60), however, 'M-60' can commonly be found even in government sources. M60 references either the first major version, or some member of the family. Other major versions are the M60E1, which was a improved version that did not enter production, the M60E2 was coaxial tank machine gun used on the M48A5 and later model M60 tanks, the M60E3 was a lightweight version, the M60E4 was another improved version called the Mk 43 Mod 0 by the Navy. The M60C was used on fix mounts on aircraft, and the M60D was primarily used as a door gun on helicopters. The M60E2 and M60D are used on the Type 88 K1 as a co-axial and pintle mounted 7.62mm MG's respectively. Their are many smaller variations among each type, or between makers of the firearm, and over time. Also, the M60 machine gun designations should not be confused with the M60 tank designations.
History
The M60 machine gun began development in the late 1940s as a program for a new, lighter 7.62 mm machine gun. The design included features that had been successful on earlier designs, as well as improvements of its own. It combined stamped sheet metal construction as on the Chauchat (the most produced MG of WWI), belt feed (as on the Browning 1919A6 and earlier designs), a modified mechanism for belt feed from the MG42, fast barrel replacement (such as on the Czech ZB 1930), and a pistol grip and stock. It is gas operated, and the system is commonly said to have been developed from the FG42s gas system (itself drawing on earlier gas designs), though at least one source says the system is borrowed from the Lewis Gun's gas system. [1]. Whatever the source, the gas-actuated operating systems was a common point of criticism. It was adopted by the US Army in 1957 (and other branches as well at other points) continues to be used currently (as of 2005). Its reputation varies widely, and often depends on which version a person gained experience and when.
The gun first became widely known during the Vietnam War period and has appeared in numerous television shows and movies (perhaps the most well-known of these are the Rambo movies starring Sylvester Stallone). It was partially replaced by the M249 starting in the 1980s in certain jobs, and was gradually replaced in the late 20th Century by the M240 machine gun (a variant of the FN MAG), which was adopted by the US military in 1991. The M240 is several pounds heavier than the M60, but it is highly regarded for its high reliability.
The M60 continued to be used a door gun on Army helicopters into the 2000s, and as the main 7.62 mm MG in some U.S. special forces in to the late 1990s and SEALs into the 2000s. As of 2005, it is used by the Coast Guard, Navy, and in a number of reserve forces, though it is gradually being phased out in favor of versions of the M240. The weapons can still be found in use in the Army, and special forces in other roles.
Use of the M60 does (did) not stop abruptly, but rather tapers off over a long period as the weapons in service slowly wear out (and then new weapons are bought) or if a new weapon is obtained for a given job. Also, sub-groups that continue to use them may obtain funding to keep models in service. One unit might have received new M240s, only to give their M60s to a reserve unit, sometimes replacing a even older weapon. It also remains in use in other countries in a variety of roles. The M240 itself has been slated for eventual replacement under a program for a new lightweight 7.62 mm machine gun.
Design
The M60 is a gas-operated, air-cooled, belt-fed, automatic machine gun that fires from the open-bolt position and is chambered for 7.62 mm NATO. Ammunition is usually fed into the weapon from a 100 round bandoleer containing a disintegrating metallic split-link belt. As with all such weapons, it can be fired from the shoulder, hip, or underarm position. However, to achieve the maximum effective range it is recommended that a bipod-steadied position or a tripod-mounted position be used and fired in 3-5 rounds bursts. The weapon is heavy and difficult to aim when firing without support, though the weight helps reduce the felt recoil. The straight-line layout allowed the operating rod and buffer to run directly back into the buttstock and reduce the overall length of the weapon. The large grip also allowed the weapon to be conveniently carried at the hip. The gun can be stripped using a live round of ammunition as a tool.
Design criticisms and problems
When tested in the field, the M60 was fairly effective, but in the jungles of Southeast Asia in which it was soon used, the initial versions displayed several potential problems when used on the ground. Some say that the most common complaint about the machine gun was its weight, but all belt-fed weapons of this type are rather heavy. The M60 was among the lightest 7.62 mm machine guns of the era, and lighter than the M240 that is slowly supplanting it.
From units in Vietnam, the single most common complaint was that the M60 was comparatively unreliable and prone to jamming and other malfunctions, especially when it was dirty (fine sand and dust in the mechanism could bring the M60 to a halt). This was a major factor in the Israeli Defense Force declining to adopt the M60. The weapon was also more difficult to clean and maintain than the M1918 Browning Automatic Rifle, or BAR. The weapon in normal conditions would often fire thousands of rounds without a serious jam, however, it is the ability to operate in the field which is important. For those who maintained the weapon properly, it was effective enough; it remained in use on aircraft, ships, and special forces after being supplanted among regular infantry by the M249 and M240. The safety was awkward to operate and worked the "wrong way" for soldiers who were trained with the M16 rifle and M1911A1 pistol - that is, it required an upward movement of the thumb on the safety catch to make the gun ready to fire, rather than a downward movement as with the other weapons.
The M60 sometimes (depending on the version) tore rims off of fired cartridge cases during the extraction cycle, resulting in failure to remove the empty case, causing a jam that could take many minutes to clear. The barrel latch mechanism (a swinging lever) had a tendency to catch on the gunner's equipment and accidentally unlatch, causing the barrel to fall out of the gun. The lever was replaced with a pushbutton mechanism that was less likely to be accidentally released, but many of the swinging-lever latches are still on guns in inventory, forty years after this problem was discovered. The grip/trigger housing assembly is held in place with a rather fragile leaf spring clip instead of the captive pins used in other designs. The spring clip has been known to be prone to breakage since the first trials at Aberdeen Proving Ground. Duct tape and cable ties have been seen on M60s in the field, placed there by their crews in case the spring clip breaks.
Several critical parts of early production M60s, such as the receiver cover and feed tray, were made from very thin sheet metal stampings and prone to bending or breaking; sturdier parts were eventually available in the early 1970s. Early M60s also had driving spring guides and operating rods that were too thin and gas pistons that were too narrow behind the piston head (part of an attempt to save weight), leading to problems with breakage. Metallurgical problems also played a part, (blamed by some on low-bid contractors), but after 1970 a slightly heavier part was designed and slowly put into the supply chain.
Another criticism with some versions of the M60 is that the barrel, removable as with most machine gun barrels, had the bipod attached to it, instead of being attached to the gas chamber or barrel shield. This had some advantages but made replacement barrels heavier.
U.S. Marines especially despised the M60 and many Marine units held onto their BARs until 1967-68 officially, and longer than that unofficially. The M60E3 variant was designed in the mid-1980s for the U.S. Marine Corps, with a reduction in weight to 18.9 lb (8.61 kg) and a slight improvement in reliability. However, users complained about the quickly-overheating barrel, which had been a problem with the original M60. This problem was aggravated in the M60E3, as the lighter barrel required changing every 100 rounds instead of every 200. However, the M60E3's barrel has a wire and plastic handle near the breech end and can theoretically be changed safely without the use of heat-resistant mittens.
In 1991, the Belgian-designed FN MAG machine gun, designated the M240 in U.S. service, was adopted by the Marines as the M240G as a replacement for M60's used by infantry, though the M240 had already been used as a co-axial and pintle MG since the 1980s by the USMC. The M240 was first adopted in 1977 by the Army as a co-axial MG. The Army adopted the M240B for infantry in the mid-90s, and other branches adopted various versions at different points. However, M60s remain in use in all branches, in addition to the U.S. Army Reserve and National Guard units. It remains in front line service with some U.S. special forces and as a helicopter door gun. The Navy also continues to use various versions in a variety of jobs. It is scheduled to be replaced as in the door gun role by the new M240H. As mentioned, both the remaining M60s and the M240 are both planned to be replaced by a new lightweight 7.62 mm machine gun.
Ammunition
The M60 family of weapons are capable of firing many different kinds of ammunition. Most common among them are the M61 Armor piercing, the M62 Tracer, the M80 Ball, the M63 Dummy, and the M82 Blank; the new tungsten cored M993 Armor piercing ammunition can be used with the M60 as well, though it did not enter the inventory until long after the M60 was withdrawn from service in active-duty units. When firing blanks, the M13 or M13A1 Blank Firing Adapter (BFA) is necessary in order to get the weapon to cycle full-auto with blanks. All of these ammunition types are delivered to the gun via a NATO standard disintegrating metallic split-link belt. The standard combat ammunition mix for the M60 consists of a four ball (M80) cartridges and one tracer (M62). The four to one ratio theoretically allows the gunner to accurately "walk" the fire into the enemy. A skilled machine gunner also knows that tracer bullets do not always fly quite the same trajectory as ball, and weapon's sights must be used—particularly at ranges in excess of 800 meters, where 7.62 x 51 mm tracer bullets usually burn out and are no longer visible (which is a problem with all weapons in this caliber; smaller-caliber tracer bullets, such as the 5.56 mm used in the M249 Automatic Rifle, hold even less tracer compound and differ greatly in weight from ordinary bullets. As a consequence, their trajectories are radically different from non-tracer bullets, and burn out at a mere 300 meters).
Summary of main types:
- M61 Armor-piercing
- M62 Tracer
- M80 Ball
- M82 Blank (is used with a blank firing attachment)
- M63 Dummy
They are all used with the M13 link (a disintegrating metal link type).
Variants
Many different variants of the M60 have been developed over the years. Most of the revisions have been aimed at rectifying problems with earlier designs; however, two versions (the M60C and the M60D) are modified for use primarily in aircraft.
Overview:
- T161 - the M60s developmental designation before it was type classified in the 1950s. Encompasses various prototype versions and the final test model that won the competition, the T161E3.
- M60 - the initial basic model, but includes many smaller changes over time with parts as well as small differences between manufacturers. It saw its first heavy use in the 1960s.
- M60E1 - a improved version that did not enter production, though many of the features were included in the the E3 and E4, and some things applied to the existing M60 production.
- M60E2 - used in vehicles as co-axial machine gun
- M60E3 - a lightweight version adopted in the 1980s.
- M60E4 (Mk 43 Mod 0) - a improved model that looks similar to the E3, but has many improvements. Used by the Navy and also has subvariants of its own. Mk 43 Mod1 is specialized version with features like extra rails.
- M60B - used in helicopters in the 1960s, but not pintle mounted
- M60C - used in fixed mounts in aircraft
- M60D - replaced M60B, and ia a pintle mounted version used especially in armament subsystem for helicopters, but also some other areas.
M60
The initial version was officially adopted by the U.S. Army in the late 1950s, though at this time it was only intended for the infantry. It was known as the T161 before it was adopted (specifically the T161E3), and was chosen over the competing T52 during testing in 1950s. They both used a similar feed and were both gas-operated, but the T161 was easier to produce and its different internals performed better.
M60E1
The M60E1 was the first major variation on the original M60. This mainly changed how the gas cylinder, the barrel, and the bipod were connected; in the first iteration they were all connected. The M60 and the M60E1 are two different versions. Some sources say the M60E1 was not formally adopted and some say it was. Either way it was not put into large production, though many of the improvements in the E1 did work there way into later versions. Also, starting in 1966, the regular M60 was modified with some of the improvements in the E1. One of the more noticeable changes on the E1 is that the bipod attachment point was moved to the gas tube rather than the barrel (like on the later M60E3). It did not have a forward pistol grip as was added on the E3 however.
M60E2
The M60E2 is used as weapon on armored fighting vehicles. It is used in the M48A5, later M60 Patton versions, and the Type 88 K1 for example. It is quite different with much of the outside gone, lacking a stock, grips, etc. It was electrically fired but had manually trigger in backup, and metal loop at the back for charging. The gas tube (the tube below the barrel) has a extension for the whole barrel length, to vent the gas outside the vehicle. This version achieved a mean time between failures of 1,669 during testing in the 1970s, less than the FN MAG, which was adopted in in 1977 as a co-axial vehicle gun, and designated the M240.
The M60E2 is used on the South Korea's Type 88 K1 tank as a co-axial, along with a M60D on a pintle mount.
M60E3
The M60E3 was fielded circa 1986 in an attempt to remedy problems with earlier versions of the M60 for infantry use of the firearm. It is a light-weight, "improved" version intended to reduce the load carried by the gunner. Unlike its predecessors, the M60E3 has several updated modern features. It has a bipod (attached to the receiver) for improved stability, ambidextrous safety, universal sling attachments, a carrying handle on the barrel, and a simplified gas system. However, these features also caused almost as many problems for the weapon as they fixed. There were different types of barrels used, but the lightweight barrel was not as safe for sustained fire at 200 rounds per minute as heavier types. However, some personnel claim to have witnessed successful prolonged firing of the weapon. The stellite superalloy barrel liner makes it possible, but the excessive heat generated by this process can quickly make the gun unusable. There were two main barrels, a lightweight barrel and a other type.
The reduced-weight components also reduced the durability of the weapon, making it more prone to rapid wear and parts breakage than the original. Most infantry units in the US Army and US Marine Corps have now switched over to the M240 as their general-purpose machine gun, which is more reliable (particularly when dirty) and seems to be well-liked by the troops for its ruggedness, despite the fact that it weighs five or six pounds more than the M60E3.
There are two main types of barrels offered with the M60E3, a light and a heavy model.
M60E4 and Mk 43 Mod 0/1
This firearm is the latest generation of the M60 family and incorporates a number of improvments over other versions. Externally it looks like somewhat like a M60E3, but it has other internal changes improvements. It features a different forward grip and is also a more reliable weapon than the other M60's. It has higher pull for the belt, and is highly configurable. It is available in a variety of configurations, and it is also possible to convert the some older models to this standard.
This version also has another designation under the Navy, Mk 43 Mod 0. The Mk 43 Mod 0 was developed for the US Navy SEALs to replace their existing stock of M60E3 machine guns fitted with shorter "assault barrels." These weapons are identical to standard M60E4s with the exception of the barrel length, and can be used either as suppressive fire or direct fire weapons, at least in terms of theory and training. The Mk 43 Mod 1 adds significantly more rail attachment points to the weapon's receiver cover and handguard.
The M60E4 and Mk43 versions are roughly similar though they are only part of the same family. While it might be fair to say that the Mk 43 are a type of M60E4, there are technical differences between any given M60E4 model. Early Mk 43 have certain differences over M60E4 from the same period, the most obvious being a duck-bill flash hider and different hand guard. Current Mk 43 do not have these differences however, and the U.S Ordnance website states as of 2005 in there FAQ, the "M60E4 and the Mk43 are the same weapon system".
The M60E4 was pitted against the (then called) M240E4 in Army trials during the 1990s for new medium machine gun for the infantry, in a competition to replace the decades old M60s. The M240E4 won, and was then classified as the M240B. This lead to 1000 existing M240 being sent to FN for a overhaul and a special kit that modified them for use on ground (such as a stock, a rail, etc.). This lead to procurement contracts in the late 1990s for all-new M240B. However, a new feature was added, a hydraulic buffer system to reduce the felt recoil as incorporated like was on the M60. While the M240B had been more reliable in the tests, it was a few pounds heavier than the M60E4, and there is program underway for a new lightweight medium machine gun in the early 2000s.
- M60E4 (LMG):
- width: 120mm (4.8 in)
- (Short Barrel): 10.2 kg (22.5 lbs), length: 958mm (37.7 in)
- (Long Barrel): 10.5 kg (23.1 lbs), length: 1077mm (42.4 in)
- (Assault Barrel): 9.9 kg (21.3 lbs), length: 940mm (37.0 in)
- M60E4 (Mounted):
- weight: 10.7 kg (22.7 lbs),
- width: 149mm (5.9 in)
- length: 1105mm (43.5 in)
- M60E4 (Coax):
- weight: 9.6 kg (21.2 lbs),
- width: 120mm (4.8 in)
- length: 1074mm (42.3 in)
M60B
The M60B was a short lived version, with limited deployment made in the 60s, to be fired from helicopters. It was not mounted, just held, and was soon replaced by the pintle mounted M60D. The B model differed most noticeably in that it had no bipod and a different rear stock than the regular model (but still had pistol grip, not spade grips).
M60C
The M60C is version of the standard M60 for aircraft-mounting (such as in armament subsystems). It lacks things like the bipod, pistol grip, and iron sights. The main difference between the standard M60 and the "C" is the electronic control system and the hydraulic swivel system used. It could be fired from the cockpit by the pilot or copilot. It is an electronically controlled, hydraulic powered, air-cooled, gas-actuated, link-belt fed weapon. system. It used the M2, M6, and M16 armament subsystems and was mounted on the OH-13 Sioux, the OH-23 Raven, the UH-1B Huey, and the OV-10 Bronco.
M60D
The M60D is a mounted version of the standard M60. It can be mounted on boats, vehicles and as a pintle-mounted door gun in helicopters. When used in aircraft, it differs from the M60C in that it is not controlled by the pilot, rather, it is mounted in a door and operated by a member of the crew. Like the rest of the M60 family, it is a air-cooled, gas-actuated, link-belt fed weapon. Unlike other models however, the M60D normally has spade grips and an aircraft ring-type sight or similar and an improved ammunition feed system. A canvas bag is also affixed to the gun to control ejected casings and links, preventing them from being sucked into the rotor blades or into an engine intake. The M60D was equipped on the UH-1B Huey (using the M23, XM29, M59, and the Sagami mounts), the CH-47 Chinook (using the M24 and M41 mounts) in both door and ramp locations, the ACH-47A "Guns-A-Go-Go" variant of the Chinook (using the XM32 and XM33 mounts), and on the UH-60 Black Hawk (using the M144 mount).
Also see US Helicopter Armament Subsystems
Civilian versions
A number of semi-automatic versions for the civilian market have been produced in the United States. The internals must be extensively modified to make it essentially impossible to convert to fully-automatic fire. If the design is approved by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE), they are treated as belt-fed semi-automatic rifles; however, individual state and local regulations still apply.
The U.S. Ordnance company is the current maker authorized by Saco to produce mil-spec M60s and M60 parts. However, U.S. Ordnance put its civilian semi-auto sales on hold until 2006 because its production capacity is required for government orders. The company charges $8000 for a new semi-auto M60.
Various makes of older fully-automatic versions are on the market as well, but there are many legal requirements to be met before purchasing them, and they cost upwards of US $20,000 - 30,000. This is largely due to the restriction on the production of fully-automatic firearms in the U.S. for the general civilian market since 1986.
See also
- M2 Machine gun
- List of firearms
- List of modern weapons
- List of individual weapons of the U.S. Armed Forces
- List of crew served weapons of the US Armed Forces
- AA-52
- Rambo (Rambo used this gun in First Blood and Rambo: First Blood II.)
Sources
- Federation of American Scientists: the M60
- Global Security: the M60E3
- Modern Firearms & Ammunition: the M60
- Department of the Army Field Manual No. 3-22.68
- US Army TACOM - Rhode Island
- MCWP 3-15.1 United States Marine Corps: "Machine Guns and Machine Gun Gunnery"
- Navy Seals
- M60E4
External links
- US Ordnance Website (Current maker of M60s)
- Nazarian`s Gun`s Recognition Guide
- Military Factory Small Arms