Arsenal Overhaul Redux is a compilation of mods designed to improve gameplay of Clear Sky.
M60E3 is a modified variant of M60, an American general purpose machine gun chambered in 7.62x51mm NATO cartridge. Currently a number of these machine guns are available on the black market, including the arms dealers in The Zone. These old M60s are not well liked due to it's low reliability in harsh conditions of anomalous zones, but are valued for their ability of effective shooting from the shoulder.
Ah yes... The good ol' M60, perfect for close/mid-range firefights, though its overall accuracy leaves much to be desired at times of course... ^^;