Back then the version we had was the Mk18 Mod 0, which we called *Philco-Fords* or *Honeywells* depending on the manufacturer and which were hand-cranked, like the old Gatling gun, feeding from a fiberglass fabric belt rather than metallic links. No, I was not in the Navy. Yes, we did swipe one of the Honeywells to mount in the loader's hatch of one of our tanks.
The Mark 19 was a post-Vietnam version, though some early Mk 19 Mod 0 or Mod 1 versions may well have been field-tested in the 1970s in the later days of the war. Nice thing about the Mk18 was that it DID use the same ammo as the M79 and XM148 grenade launchers [40mmx46SR] in 25-round belts that the ammo remained in as it fed through the gun- there was no removal of the ammo from the belt, which kept it reasonably reliable. The later Mk 19 guns used the higher-pressure 40x53SR linked round also used in the chin turret automatic grenade launcher in the chin turret of the early Huey Cobra gunships. I think the helo guns were the *Mark 20* gun in Navy small boat service, sometimes used in the gun tub instead of the twin .50s.
