This is .40 S&W Federal 155gr. HST Brass Case Ammo. Federal HST offers consistent expansion and optimum penetration for terminal performance. A specially designed hollow-point tip won't plug while passing through a variety of barriers and this bullet holds its jacket in the toughest conditions. HST is engineered to provide 100% weight retention through most barriers and impressive expansion. This ammo is brass cased, boxer primed, and non-corrosive. This ammo is packed 50rds. per box.