Abstract: A two-piece firearm projectile includes a jacket and a penetrator. The proximal end portion of the penetrator is received in and mates with a corresponding recess defined in the inside surface of the jacket. A three-piece projectile includes a jacket, a slug, and a penetrator. The slug and at least part of the penetrator are encased by the jacket, where the slug is positioned between the base of the jacket and the proximal end of the penetrator. The proximal end of the penetrator overlaps axially and mates with the distal end of the slug. In one example, a frustoconical end of the penetrator is received in and mates with a frustoconical recess in the distal end of the slug or the jacket as the case may be.