This is a very fine example of a very scarce original U.S. Army Quad 50 M45F towed gun mount that includes a fully automatic Class III/NFA M2 .50 cal HB machine gun manufactured by Group Industries in Louisville, KY. This gun mount system was originally developed in WWII (circa 1942) by the W. L. Maxson Corporation at the request of the U.S. Army. It was intended for use as a light anti-aircraft weapon in the Pacific and European theaters, due to its high rate of concentrated fire. During WWII, it was affectionately termed the "Maxson Meat Grinder"! It went on to be used throughout WWII and then remained in service through Korea and even into Vietnam. It was very effective against aircraft, fixed gun emplacements and even against advancing troops. When fitted with all four .50 cal HMGs, it could fire 40 round per second! It weighed 2500 lbs when complete and was designed to be towed behind a half-track or ammunition carrier. However, during WWII, it was also mounted in the bed of the M110 half-track and used as a mobile gun platform. When used in the half-track, the actual gun mount was removed from the M20 towed trailer and placed in a ring mount in the bed half-track. The four 50 cal heavy machine guns were arranged in pairs on each side, and the entire gun system was powered by two batteries that were recharged using a small 3 hp gas engine coupled to a generator mounted on the back side of the mount. The electric motor was used to traverse and elevate the gun system. This generator/engine system has two data plates: one marked "ENGINE MODEL NO./K90" over the engine specs and another marked with "KOHLER/ELECTRIC PLANT/MODEL 500CE1/SER. No. 220119" and additional specs. Inside the mount was a centrally located canvas gunner seat with an armored pod covering the legs of the gunner. The gun system was aimed via a centrally mounted U.S. Navy Mk IX illuminated gun sight. The sight data plate is marked "U.S. NAVY-BU. OF ORD./ILLUMINATED SIGHT/MARK IX/INSPECTOR H.T.M. NO 86212/MADE BY/WOLLENSAK OPTICAL COMPANY/ROCHESTER N.Y. U.S.A." Each machine gun was fed via a two hundred round, dome-shaped ammunition can, one mounted next to each machine gun. When all fully loaded, each gun could fire some 550-rounds per minute, and the rate of fire for all four guns was a devastating 2,200-rounds per minute. To operate the system, there were two pistol grip type handles in the center of the quadmount used to articulate to traverse and elevate the gun and which also housed the firing triggers. The quadmount will elevate, depress, or traverse at rates up to 60 degrees per second with the speed of elevation and traverse proportional to the amount of pressure/movement on the handles. To operate, you rotate the handles forward to depress the guns, and rotating them backward will elevate the guns. Pushing the left handle forward rotates the quadmount clockwise and pushing the right handle forward rotates the quadmount counter-clockwise. The gun mount system itself is marked on the data plate with "MOUNT, MACH. GUN, MULT. CAL. 50 M-45F/ORD. DEPT. U.S. ARMY/REBUILT BY BOWEN-McLAUGHLIN, INC./SOUTHERN ORD. DIV. 3 53 C A." As noted, this devastating weapon system is current equipped with only one M2 .50 Cal heavy MG manufactured by Group Industries of Louisville, KY. This weapon uses some surplus M2 parts that were mated to a new production receiver. The right side of the receiver is stamped with "MACHINE GUN/CAL. 50 M2/SERIAL NO. 200084/GROUP IND/[Louisville illegible] KY 40214." This single M2 MG has been properly converted to firing using an electronic solenoid device mounted on the rear of the receiver. The original spade grip assembly is also included, so it can be dismounted and converted back into a ground mounted version. This machine gun has the same functioning, firing, and disassembly characteristics as an original M2 HB machine gun. It is complete with five original large dome-shaped ammunition cans and two extra square .50 cal ammunition cans along with two additional electronic-solenoid device to convert any additional M2s into the correct electronic firing version.