| Year | 1942 (M51) |
| Weapon Type | [@type] |
| Origin & Designer | [@designer] |
| Numbers Produced | ? (M51) 10 |
| Crew | Sergeant/Squad Leader. Corporal/Gunner. |
| Calibre | .50 Cal (12.7x99 M2 U.S. Ball) |
| Elevation | -10° to +90° |
| Traverse | 360° |
| Breech | [@breech] |
| Recoil | [@recoil] |
| Gun Sight | M18 |
| Gun Mount | Maxson M45 |
| Carriage | [@carriage] |
| Trailers | M17 (M51) M20 (M55) |
| Gun Shield | [@gun_shield] |
| Armoured Plate | 6.4mm |
| Barrel Length | 1.14m |
| Overall Length | 1.95m. |
| Width | 2.10m |
| Height | 1.43m |
| Weight | M51: 3.128 kg M55: 1.338 kg |
| Round Weight | 117.4 g |
| Muzzle Velocity | 856 m/s |
| Feed | [@feed] |
| Magazine Capacity | 800 x .50 (in four 200 x Round Drum Magazines) |
| Practical Rate of Fire | [@practical_rate_of_fire] |
| Rate of Fire | [@rate_of_fire] |
| Maximum Rate of Fire | 2.200 rpm |
| Maximum Ceiling | 4.570m |
| Maximum Ground Range | 6.770m |
| Maximum Range | [@maximum_range] |
| Armour Penetration | 12mm @ 500m @ 30° |
| Traction | 2 ½ ton Truck (M51) 3/4 Truck (M55) |
| Variants | [@variants] |
| Notes | The US army saw how effective the quad .50 cal machine guns were when mounted on the M45 mount they requested a mobile version that could be towed truck. The M51 was composed of the M17 trailer and the M45 multiple .50 cal. Mount. The US airborne requested a lighter version able to be transported by glider and this version was called the M55. This was the combination of the M45 mounted on a lighter M20 Trailer which could be pulled by jeep. Quad .50s were usually kept under AAA Group command and issued at Divisional level. |