The cartridge’s headstamp is found on the base of the cartridge case, around the primer pocket at the very bottom of the round.

Quick Scoop

  • The headstamp is stamped into the flat end of the case where the primer sits, not on the bullet, neck, or sidewall.
  • On shotshells, it is on the metal base (brass or steel) of the shell, again surrounding the primer area.
  • This marking typically shows information such as caliber/gauge and manufacturer, and sometimes year or plant code on military ammo.

How To Spot It Fast

  1. Take the cartridge and look at the end opposite the bullet (the “bottom”).
  1. Find the primer in the center; the ring of letters/numbers around that primer is the headstamp.
  1. Rotate it like a clock face to read markings at the “12, 3, 6, and 9 o’clock” positions if present.

In short: flip the cartridge over and check the bottom around the primer— that’s where you can find the cartridge’s headstamp.

Information gathered from public forums or data available on the internet and portrayed here.