Excerpt from my article in the JOURNAL # 449.
You guys remember the fifties, don’t you? Ah the fifties. Not the decade of blue suede shoes, drive-in movies, automobile tail fins, or Elvis. I mean the FIFTIES, as in 50 CALIBER BENCHREST CARTRIDGES.
At the top of the list and most often encountered is the daddy of them all, the 50 BMG. As required by FCSA rules, any rifle competing in the Light Class must be chambered for the unaltered BMG case and must accept an FCSA approved chamber gauge. The one shown here has a 50 BARRETT headstamp and a 750-grain Hornady A-MAX UHC bullet.
Every wildcatter worth his salt will take any cartridge case he can get his hands on and try to improve it. The 50 BMG is no exception. The 50 BMG IMPR shown here is loaded with an 800-grain solid bore-rider bullet.
Many 50 caliber competitors consider the case volume of the original BMG cartridge to be more than adequate for 1000 yard shooting and they seek improvements in the form of less capacity and more precision rather than added velocity. The one shown here, the 50 McMURDO, is loaded with a 705-grain bore-rider bullet and is one of the more popular.
Another often seen cartridge is the 50 BAT. Using the military Cal. 50 Spotter-Tracer M48, M48A1, or M48A2 case, the round shown has had the primer pocket enlarged and a brass flash tube with a standard large rifle primer installed. The cartridge sports a GI 700 grain M2 bullet.
A 50 wildcat that is destined to grow in popularity is the 50 DTC. Designed by a shooter in France as the 510 DTC EUROP, it was intended for use in countries where military cartridges are prohibited. The United States version is aimed at side-stepping State laws banning the 50 BMG.
A discussion of 50 caliber benchrest cartridges would not be complete without mention of the largest of them all, the 50 FAT MAC. Developed by rifle maker Gale McMillan, the Fat Mac is made from a drastically altered 20mm Vulcan cannon case. Whereas the 50 BMG Improved can launch a match bullet to 3000 feet per second, the Fat Mac will propel the same bullet in excess of 3400 fps. Unfortunately this performance comes with a high price tag. Initial tests resulted in very short barrel life and serious copper fouling after only a few rounds fired. Attempts to mitigate these problems were only partially successful and the project was eventually abandoned.