What is the difference between centerfire and rimfire ammunition?

What is the difference between centerfire and rimfire ammunition?

• A. Centerfire uses a primer in the center of the base; Rimfire uses a primer in the rim around the base.
• B. Centerfire uses a primer in the rim; Rimfire uses the center.
• C. Centerfire uses no primer; Rimfire uses primer.
• D. Centerfire is for rifles; Rimfire for handguns.

Answer: (A)

The key idea is where the primer is located and how ignition starts. In centerfire ammunition, the primer sits in a small pocket in the center of the cartridge base. The firing pin strikes that center, detonating the primer, which then ignites the powder charge. In rimfire ammunition, the primer is mixed into the rim around the base; the firing pin crushes or peens the rim to ignite the primer, which then lights off the powder. This distinction in primer location is what the correct choice states. It’s not about the firearm type or whether a primer is present in general—both types use a primer—but where that primer resides. Rimfire cases are generally not reloadable in the same way centerfire cases are, and rimfire is typically associated with smaller calibers, while centerfire is used across a broader range of calibers.

The key idea is where the primer is located and how ignition starts. In centerfire ammunition, the primer sits in a small pocket in the center of the cartridge base. The firing pin strikes that center, detonating the primer, which then ignites the powder charge. In rimfire ammunition, the primer is mixed into the rim around the base; the firing pin crushes or peens the rim to ignite the primer, which then lights off the powder.

This distinction in primer location is what the correct choice states. It’s not about the firearm type or whether a primer is present in general—both types use a primer—but where that primer resides. Rimfire cases are generally not reloadable in the same way centerfire cases are, and rimfire is typically associated with smaller calibers, while centerfire is used across a broader range of calibers.