The Springfield Armory ST916556BMA Saint 5.56 16in M-Lok 30rd Mid-Length Black Rifle. The SAINTs flat top design is optics ready and includes a flip-up rear aperture sight and fixed A2-style front. The 16-inch Chrome Moly Vanadium barrel features a 1:8 twist rate to handle a wide range of bullet types. The operation of the M16 bolt carrier group is managed by a mid-length gas system paired with a heavy tungsten buffer, resulting in an exceptionally smooth action. A good shot starts with the trigger, so that’s why the SAINT AR-15 features micro-polished and Nickel Boron treated components. While it offers the right pull weight for defensive use, you won’t feel it.