6mm Optimum
The "6mm Optimum" is a concept popularized in 1999 by military writer Stanley C. Crist.
The 6mm AR (center) is near the "6mm Optimum". |
History
Crist argued for the adoption of a 6mm rifle chambering as a replacement for the venerable 5.56×45mm NATO and 7.62×51mm NATO, calculating that such a loading would be near the weight and minimal recoil of the lightweight 5.56 while nearer the terminal performance of the heavier 7.62, thereby permitting a single caliber to serve in general-purpose machine guns, sniper rifles, and infantry carbines.
Ballistics
Crist's specifications were that "6mm Optimum" ammunition achieve, with a 100 grain bullet:
- velocity: 2,900 ft/s (muzzle), 1149 ft/s (1,200 m)
- energy: 1,867 ft lbf (muzzle), 293 ft lbf (1,200 m)
- flight-time to 1,200 m: 2.21 seconds
- deflection @ 1,200 m in 10 mph crosswind: 151 inches
- maximum trajectory: 244 inches
...of which he noted, "...even with a conservative estimate for the muzzle velocity of the 6mm Optimum cartridge, computed data for 1200-meter velocity, flight-time, wind-deflection, and trajectory height are all greatly superior to both 5.56 and 7.62 NATO rounds."[1]
See also
References
- Crist, Stanley C. (September 1999). "Is 6mm The Optimum Caliber? A Common Cartridge for Rifle and Machinegun" (PDF). Infantry. 72 (3). Retrieved June 19, 2017.