format_quoteDeveloped by Tim LeGendre in 2007, the 450 Bushmaster is a perfectly logical development intended to maximize power in the AR-15 platform. It uses a case with the same body diameter as the 30-06, headspaces on the case mouth, and launches bullets of 0.452-inch diameter. To achieve this result, a rather thin case neck is required.
Operating at the maximum pressure that can safely be used in the AR-15, when considering the much larger case body and therefore increased bolt thrust, compared to the 223, this round more-or-less duplicates standard 45-70 ballistics, which is no faint praise. As such, it does exactly what the designer intended, delivering substantial stopping power from the AR platform.
The 450 Bushmaster is a fine cartridge that exemplifies the reality of designing a round to take full advantage of what a given platform offers. As such, it represents a good option for delivering serious medicine from a handy, quick-cycling, and accurate gun.
The Bushmaster is also the basis of the wildcat 358 Modern Sporting Rifle (MSR), designed by Todd Corder, which produces significant AR-15 platform energy. It produces 35 Remington ballistics. Trajectory is flat enough for shots to about 250 yards.
Heritage of this case dates to the 1870s with the introduction of the 40-70 Ballard case.
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