Rimfire vs. Centerfire: Why .22 Brass Doesn't Have a Removable Primer
Disclaimer: This guide is for educational and identification purposes only. It describes the manufacturing design of cartridge cases and should not be used as a substitute for proper firearms training. Always treat any ammunition component with appropriate caution.
If you've shopped our .22 caliber brass alongside our 9mm, .223, or .308 brass, you may have noticed our listings describe the primer differently depending on the caliber. That's not inconsistent copy — it reflects a real, physical difference in how these cartridges are built. Here's the explanation.
Two ignition systems, one job
Every metallic cartridge needs a way to ignite the gunpowder inside the case when the firing pin strikes it. There are two systems used to do this: centerfire and rimfire. The names describe exactly where the firing pin makes contact.
Centerfire: a separate, replaceable primer
Centerfire cartridges — 9mm, .223/5.56, .308, .45 ACP, .38 Special, and most other common pistol and rifle calibers — have a small, discrete primer cup seated in the center of the case's base. This primer is a genuinely separate physical component, pressed into a pocket machined into the brass.
Because it's a separate part, a centerfire primer:
- Can be physically removed (called "depriming" or "deprimed") using a simple punch tool or depriming press.
- Leaves the case fully reusable for reloading once removed.
- Shows a distinct dimple in the center of the base once it's been struck and fired.
This is why you'll see us describe centerfire brass as either "Intact, spent and inert" (the fired primer is still seated in the case) or "Removed / inert" (the primer has been punched out) — both are accurate descriptions of a real, physical primer component.
Rimfire: the primer is part of the case itself
.22 Short, .22 Long, .22 LR, .22 WMR, and .17 HMR are all rimfire calibers. Rimfire cartridges don't use a separate primer at all. Instead, the priming compound is spun into the hollow rim around the base of the case during manufacturing — it's not a separate part, it's built into the case itself.
When the firing pin strikes the outer edge of the case (the rim, not the center), it crushes that rim and ignites the priming compound trapped inside it. Because the compound is integral to the case:
- There's nothing to physically remove. "Deprimed" isn't a real state for rimfire brass — there's no separate part to punch out.
- Once fired, the priming compound is simply spent, the same as it would be for any other once-fired rimfire casing.
- This is true of every .22 caliber shell we sell, not a special processing step that makes one listing different from another.
That's why our .22 caliber listings describe primer status as "Spent (rimfire — no separate primer component)" instead of "Removed" or "Intact" — those terms only make sense when a discrete primer actually exists to be present or absent.
How to tell them apart at a glance
Once a case has been fired, you can actually see the difference in ignition system just by looking at where the firing pin struck it.
Centerfire: a dimple in the center. Because the primer sits in the middle of the case base, a fired centerfire case shows a small, round dimple pressed directly into the center of the primer.
Rimfire: a strike mark on the outer edge. Because the priming compound is in the rim rather than the center, a fired rimfire case shows a strike mark along the outer edge of the base instead — a short, dash-like crimp where the firing pin crushed the rim. There's no mark in the center at all, since there's nothing there to strike.
Side by side, it's an easy, reliable way to tell which ignition system you're looking at without needing to know the caliber by name.
Quick reference: centerfire vs. rimfire
| Feature | Centerfire | Rimfire |
|---|---|---|
| Primer type | Separate, replaceable component | Built into the case rim, not separate |
| Firing pin strikes | Center of the case base | Outer rim of the case base |
| Fired mark looks like | A round dimple, centered | A short, dash-like crimp on the outer edge |
| Can be "deprimed"? | Yes — physically removable | No — nothing separate to remove |
| Common calibers | 9mm, .223/5.56, .308, .45 ACP, .38 Special | .22 Short, .22 Long, .22 LR, .22 WMR, .17 HMR |
| Once-fired condition | Intact spent primer, or removed | Spent priming compound in the rim (always) |
Why this matters for craft and jewelry use
Whichever type you're working with, the safety fundamentals are identical: once a cartridge has been fired, both centerfire and rimfire brass are spent, inert, and contain no live primer, powder, or projectile. The distinction above is about manufacturing design and correct terminology — not about one type being safer or more "finished" than the other. We just want our listings to describe what you're actually holding accurately, whether that's a punch-removable centerfire primer or a rimfire case with no separate primer to begin with.
Shopping for rimfire brass? Our .22 Caliber Brass Shell Casings, Qty 1000 are cleaned, tumbled, and individually inspected — genuine once-fired rimfire brass at bulk pricing. We also carry .22 Winchester Magnum Rimfire brass for a harder-to-find caliber, and a full range of quantities and finishes in our .22 Caliber collection.