Source : Webster's Revised Unabridged Dictionary (1913)

Vickers-Maxim automatic machine gun \Vick"ers-Max"im automatic
machine gun\
   An automatic machine gun in which the mechanism is worked by
   the recoil, assisted by the pressure of gases from the
   muzzle, which expand in a gas chamber against a disk attached
   to the end of the barrel, thus moving the latter to the rear
   with increased recoil, and against the front wall of the gas
   chamber, checking the recoil of the system.