The .22 WMR stands for .22 Winchester Magnum Rimfire, a powerful rimfire cartridge favored for its increased range and kinetic energy over standard rimfire rounds. The name reflects its approximate bullet diameter and its status as a magnum length rimfire casing. Factory ammunition typically uses bullet weights between 30 and 50 grains, pushing projectiles at significantly higher speeds than traditional .22 caliber loads. It is commonly used for varmint hunting, predator control, target shooting, and self defense in compact revolvers. Because it offers a relatively flat trajectory and hits substantially harder than standard rimfire cartridges, it remains one of the most widely used magnum rimfire rounds available today.
What Is 22 WMR?
| Specification | .22 WMR | Source |
| Full Name | .22 Winchester Magnum Rimfire | SAAMI / C.I.P. |
| Cartridge Type | Rimfire | SAAMI / C.I.P. |
| Rimfire / Centerfire | Rimfire | SAAMI / C.I.P. |
| Bullet Diameter | 0.224 inches (5.7 mm) | SAAMI |
| Common Bullet Weight | 30 to 50 grains | CCI / Federal Premium |
| Case Length | 1.055 inches (26.8 mm) | SAAMI |
| Overall Cartridge Length | 1.350 inches (34.3 mm) | SAAMI |
| Typical Muzzle Velocity | 1,530 to 2,300 fps | CCI / Winchester |
| Typical Muzzle Energy | 300 to 337 ft-lbs | CCI / Winchester |
| Common Uses | Varmint hunting, target shooting, self defense | Hunter Education Organizations |
What Does 22 WMR Stand For?
The term “.22” refers to the approximate diameter of the bullet, measuring roughly twenty two hundredths of an inch. The “WMR” stands for “Winchester Magnum Rimfire”.
The cartridge was designed by Winchester in 1959 to offer a higher performance alternative to existing rimfire rounds. It is a specific, standardized cartridge with exact dimensional limits, not just a generic label for any firearm that shoots a .22 caliber projectile. The “Magnum” designation denotes its lengthened casing and increased powder capacity compared to earlier rimfire designs.
22 WMR Cartridge Type
The .22 WMR is exclusively a rimfire cartridge.
A rimfire cartridge features a thin brass casing where the bottom rim is hollow and filled with a shock sensitive priming compound. When the firearm trigger is pulled, the firing pin strikes the outer rim to crush the compound and ignite the gunpowder inside. This differs from a centerfire cartridge, which uses a thick solid base containing a replaceable, standalone primer cup in the center. Because the .22 WMR operates at higher pressures than older rimfire rounds, its brass casing is visibly thicker than standard rimfire brass, though it still relies on the rim crushing mechanism to fire.
22 WMR Dimensions
Cartridge dimensions are standardized globally by organizations like the American Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) and the European Commission Internationale Permanente pour l’Epreuve des Armes à Feu Portatives (C.I.P.). Unlike standard .22 rimfire rounds that use a “heeled” bullet (where the base of the bullet is narrower to fit inside the case), the .22 WMR uses a standard, non heeled projectile that is seated fully inside the case neck.
| Dimension | Specification | Inches | Millimeters | Source |
| Bullet Diameter | Maximum outer projectile width | 0.224 | 5.70 | SAAMI |
| Case Length | Maximum length of empty brass | 1.055 | 26.8 | SAAMI |
| Overall Cartridge Length | Maximum loaded total length | 1.350 | 34.3 | SAAMI |
| Rim Diameter | Maximum width of the rim | 0.294 | 7.5 | SAAMI |
| Case Diameter | Maximum width of the body | 0.242 | 6.1 | SAAMI |
22 WMR Bullet Weights
The most common bullet weights for the .22 WMR range between 30 and 50 grains.
- 30 Grain: Often paired with polymer tipped or specialized hollow point bullets. These lighter projectiles are designed to reach hyper velocities (often exceeding 2,200 fps) for flat trajectories and explosive expansion on small varmints.
- 40 Grain: The traditional standard weight for .22 WMR. It provides an excellent balance of speed, kinetic energy, and penetration.
- 45 to 50 Grain:Heavier bullets utilized for deeper penetration on tougher game, such as coyotes or foxes, though they travel at markedly slower velocities.
Bullet weight directly dictates how the cartridge performs. Lighter bullets shoot flatter over short distances but lose energy faster due to wind resistance. Heavier bullets arc more heavily but hit with deeper penetrating force upon impact.
22 WMR Velocity
Velocity in .22 WMR ammunition is significantly faster than standard rimfire cartridges. Actual velocity is highly dependent on the barrel length of the specific firearm being used, with rifle barrels maximizing speed and handguns seeing severe velocity drops.
- Standard 40 Grain: Typically travels around 1,875 to 1,910 feet per second (fps) when fired from a rifle barrel.
- Light 30 Grain: High performance varmint loads can reach 2,200 to 2,300 fps from a rifle.
- Heavy 50 Grain:Drops down to approximately 1,530 fps, prioritizing momentum over raw speed.
22 WMR Energy
Muzzle energy measures the kinetic power of the bullet as it leaves the barrel, calculated using the bullet’s weight and velocity.
For a standard 40 grain jacketed hollow point traveling at 1,875 fps, typical muzzle energy is published at 312 foot-pounds (ft-lbs).A lighter 30 grain bullet pushed to 2,200 fps generates approximately 322 ft-lbs of energy. Ammunition using 30 grain bullets at 2,250 fps can reach up to 337 ft-lbs of energy. These figures represent published manufacturer data from standard 24 inch test barrels. This gives the .22 WMR roughly two to three times the kinetic energy of a standard rimfire cartridge.
What Is 22 WMR Used For?
The .22 WMR is highly favored for practical applications that require moderate kinetic energy without the noise or recoil of a centerfire rifle.
- Varmint Hunting:Highly effective for harvesting groundhogs, prairie dogs, raccoons, and foxes at short to medium ranges.
- Predator Control: Often used by farmers and ranchers for managing coyotes at close distances.
- Self Defense: Due to the low recoil, many manufacturers produce compact revolvers and high capacity pistols chambered in .22 WMR specifically for concealed carry and personal protection.
- Target Shooting:While more expensive than standard rimfire ammunition, it shoots significantly flatter, making it enjoyable for medium range target practice.
22 WMR vs 22 LR
The .22 Long Rifle (LR) and the .22 Winchester Magnum Rimfire (WMR) are entirely different cartridges. They are not interchangeable.
| Feature | .22 WMR | .22 LR |
| Cartridge Type | Rimfire | Rimfire |
| Common Bullet Weight | 30 to 50 grains | 36 to 40 grains |
| Typical Velocity | 1,530 to 2,300 fps | 1,070 to 1,435 fps |
| Typical Energy | 300 to 337 ft-lbs | 102 to 183 ft-lbs |
| Case Size | 1.055 inches length | 0.613 inches length |
| Common Uses | Varmint hunting, self defense | Target shooting, training, plinking |
Because the .22 WMR uses a wider, longer case (0.242 inches in diameter versus the LR’s 0.226 inches), a .22 LR cartridge will sit loosely inside a .22 WMR chamber.Firing a .22 LR inside a .22 WMR firearm is incredibly dangerous, as the unsupported brass case will rupture upon firing, venting high pressure hot gases into the firearm action and potentially injuring the shooter.
22 WMR vs 22 WRF
The .22 WMR case was developed by lengthening the older .22 Winchester Rimfire (WRF) cartridge.
The .22 WRF was introduced in 1890 and features the same thicker case diameter as the WMR but is significantly shorter. While some modern firearms chambered in .22 WMR can safely fire older .22 WRF ammunition (acting similarly to how a .357 Magnum revolver can fire .38 Special ammunition), shooters must consult their specific firearm manual before attempting this. The .22 WMR cannot be fired in a .22 WRF chamber because the WMR casing is far too long to fit.
22 WMR vs .22 Caliber
The term “.22 caliber” strictly refers to the internal bore diameter of a firearm barrel or the general width of a projectile (approximately 0.22 inches). It is a broad size category, not a specific ammunition type.
A cartridge labeled “.22 WMR” is one highly specific application of that caliber. There are dozens of completely different cartridges that are technically “.22 caliber,” ranging from tiny .22 Short rimfire rounds to massive centerfire rifle cartridges like the .223 Remington. Knowing a firearm is “.22 caliber” is never enough information to select the correct ammunition; the exact cartridge designation must match the barrel stamp.
22 WMR Effective Range
The effective range of a .22 WMR bullet varies based on the target and the environment.
- Maximum Projectile Range: If fired at an upward angle, a .22 WMR bullet can easily travel over 1.5 miles before hitting the ground.
- Effective Range:For harvesting varmints or small predators, the round carries enough kinetic energy and maintains a flat enough trajectory to be highly effective up to 125 yards.
- Practical Accurate Range:While the bullet can fly true well past 150 yards, wind drift begins to heavily push the lightweight projectile off target at longer distances, meaning most practical hunting occurs inside of 125 yards.
22 WMR Accuracy
Quality .22 WMR rifles are inherently accurate. Unlike standard rimfire ammunition which often uses unjacketed lead round nose bullets, modern .22 WMR ammunition utilizes fully jacketed projectiles.
A copper jacket prevents lead fouling in the barrel at high speeds and allows manufacturers to utilize advanced aerodynamic shapes, such as polymer tipped spitzer bullets. This gives the .22 WMR superior ballistic coefficients compared to standard rimfire rounds, helping the bullet slice through the wind more efficiently and maintain tighter groups downrange.
22 WMR Ammunition Types
Manufacturers produce several specific categories of .22 WMR ammunition tailored to different tasks:
- Jacketed Hollow Point (JHP): The most common hunting round. The hollow cavity forces the copper and lead to peel backward upon impact, creating a larger wound channel.
- Full Metal Jacket (FMJ): Fully enclosed in copper to prevent expansion. Used when deep penetration is required or to minimize pelt damage on furbearing animals.
- Polymer Tipped: Uses a sharp plastic tip over a hollow cavity. The tip improves aerodynamics for a flatter trajectory and violently drives into the hollow core upon impact for explosive expansion.
- Personal Defense: Specialized loads engineered with faster burning powders optimized for the short barrels of concealed carry revolvers to maximize velocity and reduce muzzle flash.
Manufacturer Data vs Actual Performance
The velocity and energy specifications printed on a box of .22 WMR ammunition represent controlled testing under ideal conditions.
Manufacturers typically acquire these numbers using long, solid test barrels (often 24 inches) in climate controlled laboratories. When a shooter fires that same ammunition through a standard 18 inch hunting rifle, independent chronograph testing will show lower velocities than advertised. Furthermore, if fired through a 2 inch revolver barrel, the vast majority of the slow burning rifle powder will detonate outside the muzzle. This massive loss of pressure means a .22 WMR handgun will produce vastly lower velocity and kinetic energy than the box claims.
FAQs
What is 22 WMR?
The .22 WMR is a high velocity magnum rimfire cartridge widely used for varmint hunting, predator control, and self defense.
What does 22 WMR stand for?
The “22” refers to the approximate 0.224 inch diameter of the bullet, and “WMR” stands for Winchester Magnum Rimfire.
Is 22 WMR rimfire or centerfire?
The .22 WMR is strictly a rimfire cartridge, meaning the primer compound is spun directly into the hollow rim of the cartridge base.
What caliber is 22 WMR?
The .22 WMR is a .22 caliber cartridge, firing a projectile that measures a maximum of 0.224 inches in diameter according to SAAMI specifications.
Can I shoot 22 LR in a 22 WMR?
No. Firing a .22 LR in a .22 WMR firearm is extremely dangerous.The .22 WMR chamber is wider, meaning the smaller .22 LR brass case will rupture upon detonation and vent dangerous high pressure gas backward toward the shooter.
What is the typical 22 WMR bullet weight?
Common factory ammunition features bullet weights ranging from 30 to 50 grains, with 40 grains being the traditional standard.
How fast does a 22 WMR bullet travel?
Velocity varies by load and barrel length, but standard 40 grain rifle loads travel around 1,875 to 1,910 feet per second.
What is 22 WMR commonly used for?
It is most frequently used for hunting medium sized pests and varmints like groundhogs, raccoons, and foxes, as well as for target shooting and self defense.
Is 22 WMR good for coyotes?
Yes, but range is critical. When using properly constructed 40 or 50 grain bullets, the .22 WMR can effectively and humanely dispatch a coyote at close ranges, generally staying inside of 75 to 100 yards.
How far can a 22 WMR bullet travel?
If fired at an upward angle, a .22 WMR bullet can travel over 1.5 miles before landing, meaning shooters must always guarantee a safe and solid backstop behind their targets.