The Army had a logistically sound idea in trying to create a one-caliber, two-weapon, small arms system. Unfortunately, the wrong caliber was chosen, and a golden opportunity was lost. By insisting on developing the best 7.62mm cartridge, rather than the best possible cartridge, the logistical situation of today is at least as complex as it was in the 1940s, with the 5.56x45mm cartridge for use in the M16A2 rifle, M4 and M4A1 carbines, and M249 light machine gun, while the 7.62x51mm round is fired in the M21 and M24 sniper rifles, and the M60, M240B, and M240G medium machine guns.
One caliber can do it all. By sending a 100-grain, very low drag bullet downrange at over 2900 feet per second, the 6mm Optimum would provide snipers with the flat trajectory of the .300 Winchester Magnum. It would give machine gunners the penetration potential and tracer capability of 7.62 NATO, thereby permitting the development of an infantry machine gun that is light enough to replace both the 7.62mm medium machine gun and the 5.56mm squad automatic weapon. And, by virtue of being a compact, lightweight cartridge, with low recoil impulse, it should also allow the creation of a combat rifle that is little or no heavier than the M16A2.
The 6mm Optimum combines the best features of several existing cartridges into a compact, lightweight round that should be capable of all around performance unequaled by any other caliber. If the future brings about another quest for a single caliber common to the infantry rifle and machine gun, let the 6mm Optimum be the one for all!