BCM Muzzle Device Information
Mod 0, 2, 4, and 6 are shorter. Similar in length to an A2 flash hider.
Mod 1, 3, 5, and 7 are longer in length and predrilled to permanently mount (per BATF specs) to a 14.5” barrel to bring length out over 16”+.
Mod 0 and Mod 1 are designed primarily for recoil mitigation.
Mod 2,3,4,5,6, and 7 are designed primarily for flash reduction with muzzle rise compensation. These mods all work similar with their primary difference being the aesthetics.