Most of the time, shooters mount front sight on the picatinny rail of a free-float handguard. By definition, a free-float handguard doesn't move with the barrel. This means that when that handguard moves, the sights do to. Even properly-installed handguards move, whether it's from the weight of the firearm, a strong grip, or impact. Especially at the end, farthest from the point of attachment, and where most users mount sights. A small amount of movement can make a big difference in point of aim. Movement as little as 0.01 inches at the handguard means almost 2" at 100 yards. The solution is the Ultradyne C4 Dynamount barrel-mounted sights for consistent aim, every time! Notes:Must be used in conjunction with a 5/8"-24 Thread Ultradyne Muzzle Device such as the Ultradyne Athena Linea Compensator. FeaturesPurely Concentric Sight PictureMaximum FlexibilityWindage-Adjustable for ZeroingTool-Less Elevation AdjustmentIndexable to 45 Degrees for Offset UseIncludes 10 MOA Dynal...