Impact shredder hammers having first and second major surfaces on opposing sides, and a circumferential edge. A mounting portion includes a mounting hole that extends from the first major surface to the second major surface, and is configured to receive a hammer mounting pin for mounting in a reducing system. A distal portion includes a primary impact face to initially impact materials to be reduced and a wear edge to subsequently compress, crumble, and/or shear the material against a wall of the equipment. The hammer is provided with a plurality of alternating protrusions and recesses in the distal portion.