sentences:  The Vector uses an articulated mechanism referred to as the "Kriss Super V," which allows the bolt and an inertia block to move downward into a recess behind the magazine well.The theory is that at the end of this travel, the energy is transmitted downward rather than rearward, thus reducing the felt recoil.When fired, the barrel axis is in line with the shoulder as in the M16 rifle, but also in line with the shooter's hand.