Every Partition bullet in the Nosler line is engineered with an optimum length, weight and ogive design for maximum in-flight and terminal performance. The fully tapered copper-alloy jacket ruptures instantly at the thin mouth, yet the gradual thickening along the bullet's axis controls expansion and curls the jacket uniformly outward at high and low velocities. Nosler's integral partition supports the expanded mushroom and retains the rear lead alloy core. Enclosed rear core retains more than half the original bullet weight for deep penetration. Special crimp locks add strength to resist deformation under the pressure of heavy magnums.