- tdc mod for better range and easier hop adjustment, upgraded bucking -the hammer sears are steel and is concidered to be one of the most reliable gbbr m4 -the band on the inside on the bolt is the cradle reinforced band that has been discontinued - moe stock and pistol grip - modded BAD lever - v.1 bolt carrier with reinforced nozzle and modded for cqb fps - 3x canadian style mags