Cutting Edge's MTAC line is machined out of lead free solid copper bar stock on a CNC Swiss lathe. These are a high BC, solid bullet designed exclusively for target use at all ranges. A unique feature of this bullet is our patented SealTiteA(R) band which is a band slightly larger than caliber diameter around the bullet which was designed to eliminate fliers by preventing gas blow-by. The SealTiteA(R) band also decreases copper fouling which is typically associated with mono metal bullets. *If shooting through transonic, a twist rate increase of 1 inch is recommended (ex: 1:9"" instead of 1:10") Mfg: Cutting Edge Bullets