Minuteman 350 Introducing the Minuteman 350. Sharing the same features and upgrades as our Minuteman chambered in 5.56. In testing, the .350 Legend delivers 50% more energy than .223, 50% more penetration than .223, and 1/3 the recoil of .450 Bushmaster. You get .357 magnum power in a MSR package. Light weight, low recoil, incredibly powerful; this is the MSR redefined. Type - Direct Impingement Caliber - .350 LEGEND Barrel - 16.5" Rail Length - 14.5" Weight - 6.2 lbs Length (Collapsed) - 34"