From my reading, I understood that the
M60 was generaly considered relatively complicated to maintain and had delicate internal parts. It had several inherent flaws such as the bipods being attached to the removable barrel rather than to the gas cylinder like on the MAG and the carrying handle was attached to the body. This meant a second person had to hold the body up in order to change a hot barrel using asbestos gloves. The rear sight was zeroed rather than the front sight on the barrel so if you switched barrels you lost zero. Plus if you slammed the top cover shut while the
michlol was forward you could break it..
The later M60E3 version which looks like the one shown here was an attempt to improve it and make it easier to carry. To make it lighter the barrel was lightened and shortened however this mad the gun even less reliable and required a barrel change every 100 rounds fired
The ironic thing is that the
M60 was designed in the 1950s based on many feature of the WW2 German MG42 that the Americans were so impressed with. Meanwhile the MAG58 was developed at the same time by the Belgians based on the mechanism of the American M1918 Browning BAR. Since then the MAG has become the most popular 7.62 MG in the Western world.
About 30 years after adopting the
M60, the American realize that they made a mistake and replace the
M60 with the MAG. Of course they won't admit that they were wrong so they add a few needless accessories and call it the
new M240
see here:
http://world.guns.ru/machine/mg12-e.htm
BTW, there is a more recent attempt to make a compact 7.62 MG based on the FN Minimi/M249 SAW
http://world.guns.ru/machine/mg38-e.htm