[McCoy]

First off! You can't really compare the Lewis gun with the MG42 as there's 30 years in development between 'em in favor of the MG42. The MG42 is beltfeeded with a quickchange barrel while on the other hand the Lewis have a fixed barrel n' is magazinefeeded with 47 round drums. the only thing in favor for the Lewis is a lower rate of fire at 550 rpm while the MG42 (depending on the weight of the receiver) have a rate at 800 up to 1800 rpm n' a standard rate at 1200 rpm. The M1919A4 have a slover rate than the MG42 at 400-600 rpm n' is thus more controlable but the MG42 have the edge on the M1919A4 due to it's quick barrelchange system. The M60 that you mention doesn't really fit the bill as it's not on par with the MG42 (that they tried to copy some solutions from), it's quite simple a piece of crap compared to the MG42.

My sugestions is that it's even better to go with a M1917A1 (450-600 rpm), MG08/15 (400 rpm) or a Vickers Gun (450-600 rpm). The main reason for those three is that they're all watercooled n' is able to substain fire as long as you feed 'em with bullets n' of these three my choice would be the Vickers Gun.

Calibers then? That's nothin' that decide this question as the rounds that all above chambers is more or less equal except the .308 (M60) that have a shorter effective range than the others. .30-06, 7.92 x 57mm n' .303 have all rougly the same effective range with .30-06 the longest effective range in the bunch but the overall nastiest n' the best MOA round of 'em all is in fact the .303 Mk. VII British.