Delivering effective shot patterns that place all projectiles on a man-sized target at 7 yards, NEW Critical Defense® 410 features a unique Triple Defense® column consisting of two .35 cal. round balls topped with one non-jacketed FTX® slug. Unique to the Critical Defense 410, the .41 cal. FTX slug actually engages the gun's rifling, and contacts the target nose-on for greatly enhanced terminal performance. Each .35 cal. round ball is made of high-antimony cold-swaged lead to resist deformation and provide excellent penetration. One thing to note…this Ammo is meant for rifled barrels. If your barrel is not rifled, the slug will not spin as designed, and accuracy may suffer.