A 16″ Monobloc® barrel in 4150 CMV, 5.56×45mm NATO, mid-length gas. The rifle makes three arguments at once. First, the gas block is milled into the barrel — a conventional block is clamped, pinned or set screwed on and can shift, so the failure point is removed rather than reinforced. Second, it ships with the HM Defense HMB™ bolt carrier group, which addresses a known failure point in the bolt itself rather than in the way it is fitted. Third, it comes down to roughly 6 lb from duty weight, having given up neither of the first two. The build is fixed across all three configurations — only the finish changes.
