So I just finished my AR build and chose the 450B.
Tromix Upper
Anderson Lower & LPK
Anderson NiBo BCG
GunTech 15" Free Float
Gyphron 18" Stainless barrel
Tromix muzzle brake
Magpul grip and stock
Vortex 4x12-44 optic
Midnight Bronze Cerakote (also did myself)