Centerfire and rimfire ammunition differ primarily in where the primer that ignites the powder is located and how the cartridge is built around it.
- Primer placement: Centerfire rounds have a removable primer seated in the center of the cartridge base. Rimfire rounds have the priming compound embedded around the rim of the base, not in a separate center primer. This difference drives how the firing system interacts with the cartridge and where the firing pin strikes.
- cartridge construction and strength: Because centerfire primers are separate components, centerfire cases are typically thicker and more robust to contain higher pressures. Rimfire cases must be thinner and more delicate since the primer is formed into the rim, which limits the pressures the case can safely handle.
- power and reliability: Centerfire ammunition generally delivers higher energy, greater reliability, and is reloadable because the primer can be replaced or the case reused (in many rimfire designs, the case is not reloadable). Rimfire ammo tends to be cheaper to produce and install for low-to-moderate power applications, but it is less powerful and less reliable for hunting larger game or precision needs.
- typical use and availability: Most modern firearms used for defense, hunting medium to large game, and sport shooting use centerfire ammunition. Rimfire rounds are common for small-game hunting, plinking, and beginner training, with the .22 LR being the most famous example.
If you’d like, I can tailor this to a specific firearm or use case (e.g., target practice, small-game hunting, or defense) and compare one or two common calibers side by side.