Authored By Dan Alex (Updated: 7/19/2016):
The M60 actually had its origins in several respected German machine guns of World War 2. The excellent belt-fed MG42 was a standard part of the German Army from 1942 to 1959, replacing the expensive yet equally-successful MG34 general purpose machine gun. The MG42 was noted for its in-the-field reliability, ease of use and its durability under true fire conditions - able to spew out an impressive 1,200 to 1,500 rounds per minute. So well-known was the MG42 that American GIs developed an ear for its distinct sound when it fired, recognizing the weapon almost instantly.
The relatively advanced FG42 served the German military as a paratrooper's selective-fire automatic rifle and from 1942 to 1945. Though limited in outright numbers, its combination of size (no bigger than even the standard German Kar 98K bolt-action rifle) and firepower made it a highly portable and yet lethal battlefield implement.
To these ends, American engineers at Saco Defense utilized a modified form of the feed system of the MG42 and the bolt and locking system of the FG42 when designing their new machine gun to a new US Army requirement. The American prototype model became the "T44", retaining some of the look of her German predecessors including the long, squared-off stock, pistol grip and forward-placed bipod assembly. The pistol and trigger group were situated near the middle of the overall design with a ribbed handgrip just ahead. The belt feed mechanism was set off to the left side of the upper portion of receiver. A new easier-to-maintain gas system was developed and fitted to the design. The barrel was specifically designed for quick-changing in the field, denoting its sustained fire role where overheating of the barrel was a sure possibility. Of note here is that this Saco design (becoming the M60) became the first American machine gun to feature the quick-change barrel.
It is also noteworthy that the Americans attempted to outright copy the German MG42 during the war, producing the T24 Machine Gun prototype by Saginaw Steering Gear. However, when it was feared that the cartridge could prove too powerful for the copied design, the project was abandoned in whole.
The T44 was evaluated alongside the competing belt-fed, gas-operated T52 in the 1950s. The T52 was derived from the FG42 itself. The T44 edged out the T52 by way of its reliability under fire and its friendly production make up. The system later received the developmental designation of "T161" before becoming the official "M60" in 1957.
Externally, the M60 has always maintained something of a unique and readily identifiable appearance. Her long stock was squared off, in some ways mimicking the German guns she was based on. The long stock assisted in stability and allowed for a shorter overall weapon. The installation also served as home to the pistol grip and trigger system. The ammunition feed system (for belt ammunition only) was positioned just above the pistol grip with cartridges entering the receiver from the left side and existing out from the right. The ammunition was to be kept in a covered though ventilated container for optimal performance. The rear sight on the receiver was of the flip-up type variety and adjustable while the forward sight only became fully-adjustable later in the M60s production life. The forend served as the forward grip before the addition of a dedicated forward pistol grip debuted in the M60E3. The gas cylinder under the barrel became an identifying characteristic of the M60. The barrel, with its integrated fixed sight, protruded out over the gas cylinder and sported the collapsible integrated bipod assembly, hinged under the barrel itself. The bipod would eventually be relocated apart from the barrel in future M60 forms to help ease barrel changing. Though not the cleanest of designs, the M60 was nonetheless an image born for the utilitarian role it had been designed for.
The M60 weighed in at 23.15lbs and featured an overall length of 43.5 inches, with 22 inches of this made up by the barrel system. The weapon fired the 7.62x51mm NATO cartridge from a gas-operated, open-bolt firing action. The feed system took on the M13-series disintegrating belt and could spew out a rate-of-fire of 600 rounds-per-minute at a muzzle velocity of 2,800 feet per second. Effective range was out to 1,200 yards while maximum range (at the expense of accuracy) was well further.
The M60 made use of several ammunition types in her day. The primary combat cartridge was the M80 Ball which was used in conjunction with the M62 Tracer round in a "four-then-one" arrangement. This meant that for every four M80 Ball rounds fired, a single M62 Tracer round would appear in the circulation, this assisting the operator in aiming his successive shots (called observing the "fall-of-shot") and make the necessary adjustments as needed. While the M80 Ball primarily served to tackle personnel directly, the M61 Armor-Piercing (AP) round was designed to combat light armored vehicles. Training rounds include the M63 Dummy and the M82 Blank - the latter utilized in field exercises and requiring use of a special attachment known as the M13A1 Blank Firing Adaptor (or "BFA") over the muzzle. Ammunition was supplied via the M13 disintegrating metallic split-link belt for all ammunition types, this usually in 100-round count.
As noted in many sources, the M60 was not a weapon without flaw. Many direct operators of the M60 noted a laundry list of items from their past experiences when using the weapon, particularly the early-form M60, and especially when moving on to something newer like the M240 or M249 machine guns. One of the biggest drawbacks of the early M60 was in how the bipod and gas cylinder was attached to the barrel. As these systems were design for squad support action in the sustained fire role, the changing of the barrel was expected for optimal performance (to prevent overheating). As such, the barrel needed to be replaced within time. By the removing the barrel, however, the bipod and gas-cylinder were removed as well, leaving no visible means of support for the operator to brace the weapon on during the barrel changing process. Most 'gunners were forced to hold the M60 up while changing the barrel. As expected, the extra barrel came equipped with its own bipod and gas cylinder attachments, making a simple barrel change a clunky and time-consuming procedure. To add insult to injury, the barrel featured no handle to grasp during the procedure, leading to the issuing of bulky asbestos gloves as a standard part of the field goods. The gloves served to protect the user from handling the hot barrel but also added yet another tool to the complicated M60 kit. Mind you that an M60 operator, if having lost this asbestos glove, was at a distinct disadvantage when "things" hit the fan.
Other reports showcased the weapon's cheap sheet-metal stamp work, this over the receiver and making up the feed tray system. The gas piston was also non-adjustable as a fixed regulator was used instead. The sight system was off-noted as poor with the forward non-adjustable sight fixed to the barrel while the rear sight needing readjusting after each barrel change. The charging handle was somewhat weak and known to break in the heat of combat. The bolt and rod assembly would most assuredly destroy one another over time through constant though typical use.
Though the M60 tested out relatively fine in her controlled evaluations, this including the firing of thousands of rounds of ammunition without issue, in-the-field actions most certainly brought out the worst in any weapon - no matter the pedigree.
As a general purpose light machine gun, it became little surprise to anyone that the M60 reached as many military-based platforms as she did during her tenure. Not only serving as a squad support weapon alongside infantry squads, the M60 could be fielded on naval patrol boats, naval vessels of size, helicopters, fixed-wing aircraft, wheeled vehicles (armored and unarmored) and tracked vehicles to include both armored fighting vehicles and main battle tanks.
In theory, the M60 could be fired from a variety of positions as assumed by the operator. This included firing from the shoulder, from the prone position or "from the hip". In practice, the latter was best reserved for Hollywood and its John Rambo exploits. Any trained soldier would see to it that he make himself as small a target as possible. Additionally, firing from the hip did not produce the most accurate of results. The M60 could make use of its standard integrated bipod assembly for stability or be fielded with a collapsible tripod instead. As a general purpose machine gun, the M60 became equally adept for the offensive or defensive role in support of infantry teams and the like, often times called to target enemy infantry directly or enemy machine gun teams.