Taber - Officially the M1919A4 is a Light Machine Gun. The .50 Browning is a Heavy Machine Gun. The M1919A6 was a move to not only lighten the gun, but to make it tactically handier ala the German MG34 and 42. Hence, not only the lightened barrel and elimination of tripod and traversing gear, but also the carrying handle and buttstock.
That said, I agree with you. As an assistant gunner, I carried the gun. The gunner carries the tripod. On long marches in hot weather, it was miserable as it had no carrying handle, and the receiver of the gun is all sharp edges, while the barrel cooling jacket is relatively small in diameter and with the holes (more sharp edges), was equally uncomfortable if carrying over one shoulder. At 34 pounds or so, if I remember correctly, it was a miserable gun to carry, although a good gun for practical rate of fire and reliability. The 1919A6 was somewhat easier to carry, and the gunner got stuck with the job! All the assistant gunner had to carry was spare barrels, if available and being fielded, or a can of ammo.