Rimfire cartridges power millions of rifles worldwide, serving as the foundational entry point for target shooters, hunters, and plinkers alike. Unlike centerfire ammunition that houses its primer in a distinct pocket centered in the base, rimfire ammunition features priming compound spun directly into the hollow folded rim of the brass casing. When the firing pin strikes anywhere along that rim, it crushes the compound against the interior wall, creating the spark that ignites the powder charge.
This simple yet ingenious mechanism eliminates the separate primer manufacturing step, keeping production costs low and making rimfire rounds remarkably affordable. Yet, despite their reputation as mere practice rounds, these cartridges possess complex histories, precise ballistic profiles, and specific operational quirks that every shooter needs to understand to get the best performance out of their firearm.
History and Evolution of Rimfire Ammunition
The rimfire era began in the mid-nineteenth century when French gunsmith Louis-Nicolas Flobert developed the first commercial self-contained metallic cartridge in 1845, followed by the commercialized .22 Short in 1857. Flobert's original design was essentially a lead ball seated atop a percussion cap with no gunpowder at all; the primer charge alone propelled the projectile. This low-powered round was designed strictly for indoor gallery shooting.
American firearm designers quickly realized the potential of this ignition system. Horace Smith and Daniel Wesson scaled up Flobert's concept, adding gunpowder to create the .22 Short cartridge for their first revolver. By 1887, the Arms Corporation introduced the .22 Long Rifle (.22 LR) by combining the case of the .22 Long with the heavier 40-grain bullet of the .22 Extra Long. That single combination outlived almost all of its nineteenth-century contemporaries to become the most popular and manufactured rifle cartridge in human history.
Major Rimfire Calibers Compared
While the .22 LR dominates discussions, modern rimfire shooting spans several distinct calibers designed for different velocity thresholds, effective ranges, and game sizes.
.22 Long Rifle (.22 LR)
The undisputed king of rimfire volume, the .22 LR fires a 30-grain to 40-grain lead or copper-plated bullet at velocities typically ranging from 1,000 to 1,250 feet per second. Standard-velocity loads stay just below the speed of sound, making them exceptionally accurate because they don't experience transonic destabilization when crossing the sound barrier. High-velocity and hyper-velocity loads push past 1,400 feet per second, flattening the trajectory slightly at the expense of terminal accuracy in certain barrels.
.22 Winchester Magnum Rimfire (.22 WMR)
Introduced in 1959 by Winchester, the .22 WMR utilizes a longer, thicker case that cannot be safely chambered in a standard .22 LR firearm. It operates at much higher pressures, driving a 30-to-50-grain bullet at speeds up to 2,200 feet per second. This extra velocity provides devastating terminal energy on small-to-medium pests like coyotes and raccoons out to 125 yards, doubling the practical envelope of rimfire hunting.
.17 Hornady Magnum Rimfire (.17 HMR)
Hornady revolutionized modern rimfire performance in 2002 by necking down the .22 WMR case to accept a tiny .17-caliber bullet. The result is a laser-flat trajectory with muzzle velocities touching 2,550 feet per second. It's built specifically for precision varmint hunting, offering explosive fragmentation upon impact and minimal wind drift compared to traditional .22 loads.
.17 Hornady Mach 2 (.17 HM2)
Built as a lower-cost alternative to the .17 HMR, the .17 Mach 2 is based on a necked-down .22 LR Stinger case. It delivers flat trajectories and high velocities similar to its bigger sibling but operates at shorter practical ranges of up to 100 yards, bridging the gap between standard .22 plinking and specialized varminting.
Ballistic Performance and Effective Range
Understanding how rimfire rounds behave downrange prevents frustrating misses in the field. Because rimfire bullets are lightweight and travel at subsonic or trans-sonic speeds, they drop quickly past 50 yards.
A standard .22 LR zeroed at 50 yards will typically drop around 3 to 4 inches by 100 yards, and more than 15 inches by 150 yards. Wind drift also plays a massive role; a ten-mile-per-hour crosswind can push a .22 LR projectile several inches off target at 100 yards.
In contrast, the .17 HMR drops less than 2 inches at 100 yards when zeroed at that distance, making it much more forgiving for hunters who need quick point-and-shoot capability without dialing scope turrets. However, the ultra-light .17-caliber bullets bleed velocity rapidly due to atmospheric drag, meaning their kinetic energy drops off sharply past 150 yards despite their flat flight path.
Advantages and Limitations of Rimfire Systems
Rimfire shooting offers distinct benefits alongside unique operational constraints that influence maintenance routines and hardware selection.
Key Advantages
- Cost Efficiency: Bulk packaging allows shooters to practice foundational marksmanship fundamentals—such as trigger control, breathing, and stance—without breaking the bank.
- Minimal Recoil: The gentle push of a rimfire cartridge allows new shooters to build confidence without developing a flinch, while letting experienced marksmen spot their own bullet trace and impacts through high-magnification optics.
- Low Noise Signatures: Unsuppressed rimfires are relatively quiet compared to centerfire rifles, and when paired with a quality suppressor, standard-velocity .22 LR rounds produce hearing-safe reports ideal for backyard pest control or quiet range sessions.
Operational Limitations
- Non-Reloadable Casings: Because the base of the brass is crushed during ignition, rimfire cases cannot be safely deprimed and reloaded with fresh powder and bullets. Once fired, the brass goes straight to the scrap bin.
- Ignition Consistency: Rimfire manufacturing tolerances can occasionally yield uneven priming compound distribution, leading to sporadic "duds" or inconsistent muzzle velocities compared to match-grade centerfire ammunition.
- Lead Fouling: Traditional unplated lead bullets leave soft lead deposits in rifling grooves, requiring regular cleaning with solvent and bronze brushes to maintain match-grade accuracy.
Choosing the Right Rimfire Rifle Action
Selecting the proper action type depends entirely on your intended use case, whether that's casual plinking, competitive precision shooting, or small-game hunting.
Bolt-Action Rifles
For absolute accuracy, bolt actions remain the gold standard. They lock up tightly, accept a wide variety of ammunition types without relying on recoil energy to cycle, and allow shooters to manually chamber rounds smoothly. Rifles like the CZ 457 or Savage B22 series demonstrate how precision-engineered rimfire bolt guns routinely achieve sub-MOA groupings at 50 yards.
Semi-Automatic Rifles
Semi-automatics cycle the next round using blowback energy generated by the expanding propellant gases. The Ruger 10/22 stands as the definitive example, offering endless modularity and fast follow-up shots. Note that semi-autos can be finicky with low-velocity or standard-velocity ammunition, as light loads may not provide enough energy to cycle the bolt fully, causing stovepipes or failure-to-feed malfunctions.
Lever-Action and Pump-Action Rifles
Lever-action rimfires offer traditional aesthetics and fast manual repeating capabilities, making them popular for casual field use and youth training. They handle mixed ammunition lengths well in certain tube-magazine configurations, letting you shoot .22 Short, .22 Long, and .22 LR interchangeably in select vintage firearms.
Maintenance and Care for Rimfire Firearms
Rimfire guns get dirty fast. The combination of lead bullet lubrication, soft lead shaving, and rimfire priming residue creates a sticky carbon buildup inside chambers and actions.
- Clean the bore from the breech to the muzzle whenever possible using a pull-through bore snake or a cleaning rod equipped with a muzzle guard to protect the delicate crown.
- Scrub the chamber face thoroughly with a nylon or bronze brush dipped in solvent. A ring of carbon often forms right at the point where the bullet transitions into the rifling lands; if left uncleaned, this ring jams newly chambered rounds and spikes chamber pressures.
- Keep the bolt face and extractor claws free of wax and lead residue. Rimfire wax coatings melt under heat and accumulate in extractor recesses, eventually causing failure-to-extract issues.
- Lubricate sparingly. Excess oil inside a rimfire receiver attracts unburnt powder granules and dust, turning into a thick sludge that causes sluggish hammer strikes and light primer hits.
Frequently Asked Questions
Can you dry-fire a rimfire rifle?
Dry-firing many modern rimfire rifles won't cause immediate damage because modern firing pins are designed to stop short of striking the chamber edge. However, older or vintage rimfire firearms feature firing pins that can peen the chamber mouth if dry-fired repeatedly without a snap cap or dummy round in place. Check your owner's manual before dropping the hammer on an empty chamber.
Why do some .22 LR rounds fail to fire?
Rimfire misfires usually stem from missing priming compound in a localized spot along the rim. If you experience a click instead of a bang, wait five seconds keeping the muzzle pointed downrange, eject the round, rotate it roughly 180 degrees in the chamber, and try firing it again. The firing pin will strike a fresh section of priming compound and usually ignite the propellant successfully.
What is the best ammo for hunting small game?
Hollow-point copper-plated bullets traveling at standard or moderate high velocities work best for small game like squirrels and rabbits. They expand reliably upon impact for clean ethical harvests without destroying excessive edible meat, unlike hyper-velocity solid bullets that can cause excessive tissue damage.
How far can a .22 LR bullet actually travel?
A standard .22 LR projectile fired at an elevated angle can travel up to a mile and a half (approximately 2,400 yards). Even though the bullet drops below terminal hunting velocity quickly, it retains dangerous kinetic energy over significant distances, making strict backstop awareness mandatory during every shooting session.
Why do match-grade .22 ammunition boxes cost so much more?
Match-grade ammunition undergoes strict quality control during manufacturing to ensure uniform case dimensions, consistent powder charges, and precise bullet weight sorting. This rigorous quality assurance minimizes velocity spreads, which translates directly into tighter group sizes at 50 and 100 yards. For more details on precision rimfire setups and community gear reviews, you can explore resources like Rimfire Central.
