50 McMILLAN FATMAC

Research notes

The 50 Fat Mac was developed in 1996 by Gale McMillan from a 20mm Vulcan cannon case. Their primary goal was to create a modern (short/fat) case like those now used in bench rest competitive events, but designed to launch .50-caliber match bullets for use in 1,000-yard (or longer-range) Fifty Caliber Shooters Association (FCSA) matches. The primer pocket has been modified to accept a steel insert and this bushing insert sizes the primer pocket to accept a .50 BMG primer and doubles as a flash tube. The latter carries the primer blast to near the front of the powder charge, which provides significant internal ballistic benefits, including improved shot-to-shot uniformity and increased muzzle velocity. Whereas the 50 BMG Improved can launch a match bullet to 3,000 feet per second, the Fat Mac will propel the same bullet in excess of 3,400 fps. The experiment however never yielded the results that Gale McMillan had hoped for and it was eventually abandoned.