M60 by supasinper

The M60 is a gas-operated automatic weapon firing the 7.62x51mm NATO round in a disintegrating link belt. It has an interchangeable barrel, built in folding bipod and can be to be mounted on a tripod or a vehicle mount.

The M60 universal machine gun was designed in the late 1950's and it's design borrows from WWII German weapons - the belt feeding mechanism is from the MG42 and the FG42's bolt and locking action are used.

The M60 has some major problems these include: the bipods and the gas chamber are permanently attached to the barrel, so quick replacement of the hot barrel was very hard (for this reason the gunner was issued with a heat proof glove).

The barrel should be changed after 200 rounds of the rapid fire but can last much longer if the gunner fires in short bursts. The M60 was adopted by US military in 1960 and served until it was replaced by the M60E1 the only difference between the two is that on the M60E1 the bipod and gas cylinder are attached to the gun not the barrell also there is a handle on the barrell that removes the need for the heat proof glove, in this form the M60 m60 service till 1994 when it was replaced by the M60E3.

The M60E3 was designed as a more handy version this was done by adding a forward handgrip and giving it a shorted butt, although the barrell could be changed from the light, short assault barrell to a longer, heavier one for sustained fire missions, like in the M60E1 the bipod is attached to the receiver, also the trigger guard has been enlarged to accomodate the gunners's finger in heavy winter gloves. The lightening of the gun during construction vastly dropped the reliability of the gun. The new, light barrel was capable of no more than 100 rounds in rapid fire. 200-300 rounds rapid fire without replacing the barrel could simply destroy it. The reliability of the M60E3 (used by USMC) was even worse than of original M60, this lead to it's replacement by the FN M240G.

M60 by Xian Saint

General purpose machine gun system

Development
The US Ordnance M60 is the US Army's general purpose machine gun and entered service in the late 1950s. The prime producer was Saco Defense, then a subsidiary of the Chamberlain Manufacturing Corporation (now General Dynamics Weapon Systems). US Ordnance produces the M60 series under licence by General Dynamics Weapon Systems.

The original design had some interesting features. The straight line layout allows the operating rod and buffer to run right back into the butt and reduce some of the overall length. The large forehand grip is most convenient for carrying at the hip and the folded bipod legs continue the hand protection almost up to the muzzle. The gun can be stripped using a live round as a tool.

The M60 fires in full automatic mode only, at a cyclic rate of 500-650 rds/min. This is slow enough for an accomplished firer to get off a single round. The tactical rate rapid is 200 rds/min.

The M60 originally used the German MG42 feed system employing an arrangement of inner and outer feed pawls driven by a bolt operated feed lever constructed to move in opposite directions, moving the belt in two stages as the bolt moved back and forward again.

As the M60 was developed, the feed system changed. The friction roller at the back of the bolt was retained as was the feed arm on top of the feed cover in which it operated. The inner and outer pawl system was abandoned and a single pawl system substituted. In this the roller, carried by the bolt moving forward, swings the feed arm to the right. The feed arm is pivoted so that the front end carrying the feed pawl slips to the left over the next round to be fed. As the bolt goes back the pawl moves to the right and lifts the entire weight of the belt through one complete pitch.

On the M60, the gas cylinder and the bipod are both permanently attached to the barrel. The M60E3 has a barrel with gas cylinder only, as the bipod is attached to the front of the receiver assembly. The barrel is chromium plated and also has a Stellite liner in the 152 mm (6 in) of barrel forward of the chamber.

The M60, having a fixed foresight, makes adjustment for zeroing on the rearsight. This means that the number one on the gun must first recognise which barrel is in the gun and secondly know the correct zero setting for both elevation and line for that barrel. In practice this means all barrels are fired from a common zero and the consequent loss of accuracy is accepted.

A variety of fire-control systems and mounts is available. Day and night sights, laser aiming devices and laser range-finders are attached and detached from the weapon brackets with the US Army dovetail mounting configuration and advanced throw-lever attachment device, without loss of zero.