The sub-x bullet used in subsonic rifle features a lead core.Long grooves in its gilding metal jacket combine with the bullets flat profile and the patented flex tip insert within its hollowpoint cavity to help it expand reliably at low velocities.Caliber: 450 BushmasterBullet Type: Sub-XBullet Weight: 395 gr (2)Rounds Per Box: 20Boxes Per Case: 10Application: HuntingCasing Material: BrassHazair: YesAmmunition cannot be shipped to a P.O. Box, please use a physical address during checkout. For restricted state buyers (CT, IL, MA and NJ), please email a copy of your state's credentials, and a photo ID along your order number to ffl@firearmsdepot.com&nbsin 5 business days to avoid cancellation and refunding your order. For California and New York buyers, please have your dealer email us a copy of their FFL or Ammo Vendor License along with your order number to ffl@firearmsdepot.com within 5 business days to avoid cancellation and refunding your order. Your order will not ship without us receiving this information. Thank you for your cooperation