#6x45mm

In this installment, we’ll be looking at a very unique round. The 6mm SAW was probably the first small arms round ever designed using computer-calculated parametric analysis, and it was also probably the first American rifle round designed from the outset for steel cartridge cases. The initial design parameters were for a round effective to 1,000 meters, and which accepted a tracer that would give a visible daylight burn out to 800 meters, and this resulted in a caliber of 6mm with a 105 grain slender steel-jacketed lead-cored bullet possessing a high length/drag ratio. Although fired at modest velocity, the sleek bullet retained its energy extremely well, giving the round good long-range penetrating power, especially compared to the 5.56mm rounds at the time. Ultimately, the 6mm SAW succeeded in its ballistic goals, but was rejected on logistical grounds, as the idea of fielding three different rounds (5.56mm, 6mm, and 7.62mm) was not considered feasible.

It’s not so unusual to hear of sub-MOA accuracy or better from a well-tuned rifle. Bringing the accuracy of a rifle below half-MOA, though, is a challenge to the gunsmith and shooter alike, and every increment below that is an increasingly difficult challenge. Sub-1/3 MOA from a rifle is definitely an achievement for the gunsmith, shooter, and handloader each.

The 6x45mm SAW was an experimental round developed by the US Army in the 1970s.