The M60 Machine Gun
(more than you wanted to know)
fires at approximately the same rate as the heavier guns it is replacing.
The M60 Machine Gun is a lightweight, general-purpose machine gun, developed to replace the following U.S. Caliber .30 machine guns: M1919A4 and M1919A6, air-cooled, and M1917A1, water-cooled machine guns.
The M60 General Purpose Machine Gun weighs 23 pounds, including bipod as opposed to 32-42 pound guns it replaced. Ammunition is the NATO 7.62mm cartridge, the same as is used in the Springfield M14 rifle. The lightweight of the new gun makes it readily portable by one man.
The gun can be fired from the shoulder (as a rifle), from the hip or prone with bipod or tripod. This flexibility makes it a general-purpose weapon capable of performing satisfactorily under all tactical conditions.
The ability of the M60 gun to replace the previous heavy water-cooled machine gun results from the fact that the barrel and gas system can be replaced in a matter of seconds due to the incorporation of a fixed headspace.
One of the objectives in development of guns of this type for infantry use is the low cycle rate. Reliable performance at low cycle rate is relatively difficult to reach in weapons in the lower weight levels. The M60 gun
"The M60 had a long development history, the first steps toward replacing the ageing Browning M1919 having been taken in 1944, when engineers at theSpringfield Armory mated the ammunition feed system of the MG42 with the action of the FG42 (both were German machine guns used during WW II) to produce an experimental gun known eventually as the T44, retaining the 7.92mm x 57 chambering of the originals. However, the new gun was to have no user-adjustable means of regulating gas flow - an unusual solution to the problem, which plagued the designers of gas-operated guns from the outset. The gas passages of such a gun rapidly became fouled with the by-products of combustion, and it is normally necessary to introduce a regulator to compensate, allowing more gas into the actuating cylinder as the system becomes constricted. The FG42 dispensed with this necessity by a form of demand regulation known as the constant pressure system: the gas enters the cylinder through a drilling connecting it with the bore (as usual) but via a second drilling in the long hollow head of the piston within. When sufficient pressure has been built up to overcome inertia (this occurs in a matter of milliseconds, of course, during the interval between the round clearing the bore drilling and leaving the muzzle) the piston is pushed backwards to begin the actuating stroke, the first effect of which is to move the drilling of the piston head out of alignment with the one from the bore into the cylinder, shutting off the gas supply. In theory, such a system is foolproof, but in practice it is not dirt - and dust-proof, and this aspect of the M60 has proved to be extremely sensitive to contamination by foreign bodies.
Eventually, a version known as the T161E3 was produced, chambered for the7.62mm x 51 NATO cartridge, and it was this gun which became the M60, being authorized for issue in 1959. As if to add insult to injury, the M60 in its basic form cost over four times as much as its rather better contemporary, the MG42/59, when it was finally adopted. It saw action throughout the Vietnam war, and, as a result of shortcomings observed in combat, no less than twelve major modifications (including a complete redesign of the gun's front end) were necessary to turn it into a practical infantry weapon, but before the modified gun (known as the M60E1) could be brought into general service, the entire concept of the 7.62mm caliber infantry machine-gun came under review by the U.S. Army and was rejected, whereupon the M60 was phased out, starting in 1986, in favor of a switch to 5.56mm caliber and the Squad Automatic Weapon (SAW)." - Roger Ford
"The pig (as the M60 was known) belonged to the guy with experience, the guy who could keep cool in a fire-fight, a guy that knew what he was doing, and not to a guy that was green. It was the only major firepower in our entire platoon. Your automatic weapons fire was your heavy artillery; the pig had greater range. It was your heavy heavy. If a man panicked and really didn't know how to handle the heavy heavy, you really didn't have too much. A lot of guys didn't want to carry it because it was very heavy and it was lethal - meaning it was lethal to both you and to Charlie. Obviously, Charlie tried to knock you out first. They tried to hit you with RPGs. Their first target of interest was the guy with the machine gun. If they knocked out that machine-gun, they could easily overrun the platoon. Then the only thing they had to contend with was just light weapons....
The fault of a lot of guys with the M60 and the reason why they used to get wiped out was because they would fire the M60 wildly. Like Young was doing that day, clips flying all over the place. He had his eyes shut, just pulling the trigger. Shit, the lead was all going up in the Goddamn treetops. Charlie was just sitting down there on the ground waiting to beam our ass. So I kept the forearm weight on it to hold it level. I took aim through the big sight right on the end of the barrel. I had to ignore the vibration, watch the sight, keep it leveled downward. I used to keep it leveled at where a man's waist would be. That was how I would decipher how low I was going to shoot it. If I thought a man was up in the treetops, I'd level it right where I thought that treetop was, and I'd shoot down just about a foot and I would be lethal. I'd blow the guy out of there." -
Ford, Roger. THE GRIM REAPER: MACHINE GUN AND MACHINE-GUNNERS IN ACTION.
Sarpedon. N.Y., N.Y. 1996.
SA-NM3-1704 - NOTES ON DEVELOPMENT TYPE MATERIEL FOR M60 MACHINE GUN, 7.62MM, AND M2 TRIPOD MOUNT (MODIFIED). P.W. Marshall. 27 August 1959.
SA-TN3-1707 - 7.62MM M60 MACHINE GUN BUFFER ASSEMBLY EVALUATION, by A.H. La Riviere. 12 October 1962.
SA-TN3-1708 - DEVELOPMENT TESTING OF BLANK FIRING ATTACHMENT FOR THE GUN, MACHINE, 7.62MM, M60, by F.A. Wakefield. 16 January 1963.
Designed as a replacement for the Browning Automatic Rifle (BAR) but never released to units. Due to its light weight, approximately 15lbs, it was uncontrollable during full automatic fire. The barrel quickly overheated and created a "heat wave" effect in the shooters line of sight. Good idea, bad results. The M60 eventually became the BAR of Vietnam as well as the squad heavy machine gun.