SinterFire Special Duty Ammunition brings to bear the devastating effects of frangible when couple with a hollow point. Protect you home with a reduced chance of over-penetrating walls while still having exceptional performance. All SinterFire lead-free, frangible projectiles are manufactured using an exclusive blend of copper and tin composite material and a proprietary heat treatment process. SinterFire is the originator and innovator of this technology used by government, military and law enforcement personnel since 1998.