| .22 Winchester Magnum Rimfire | ||
|---|---|---|
.22 Winchester Magnum Rimfire |
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| Type | Rimfire | |
| Place of origin | United States | |
| Production history | ||
| Designed | 1959 | |
| Manufacturer | Winchester | |
| Produced | 1960–present | |
| Specifications | ||
| Parent case | .22 WRF | |
| Bullet diameter | .224 in (5.7 mm) | |
| Neck diameter | .242 in (6.1 mm) | |
| Base diameter | .242 in (6.1 mm) | |
| Rim diameter | .294 in (7.5 mm) | |
| Rim thickness | .050 in (1.3 mm) | |
| Case length | 1.055 in (26.8 mm) | |
| Overall length | 1.350 in (34.3 mm) | |
| Rifling twist | 1-16" | |
| Primer type | Rimfire | |
| Ballistic performance | ||
| Bullet weight/type | Velocity | Energy |
| 30 gr (1.9 g) HP | 2,200 ft/s (670 m/s) | 322 ft·lbf (437 J) |
| 40 gr (2.6 g) JHP | 1,910 ft/s (580 m/s) | 324 ft·lbf (439 J) |
| 50 gr (3.2 g) JHP | 1,650 ft/s (500 m/s) | 300 ft·lbf (410 J) |
| Test barrel length: 24 inches (610 mm) Source(s): Cartridges of the World [1] |
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The .22 Winchester Magnum Rimfire, more commonly called .22 WMR, .22 Magnum, or simply .22 Mag, is a rimfire rifle cartridge. Originally loaded with a bullet weight of 40 grains (2.6 g) delivering velocities in the 2,000 feet per second (610 m/s) range from a rifle barrel, .22 WMR has also been loaded with bullet weights of 50 grains (3.2 g) at 1,530 feet per second (470 m/s) and 30 grains (1.9 g) at 2,200 feet per second (670 m/s).
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The .22 WMR was introduced in 1959 by Winchester, but was not used by Winchester until the venerable Winchester Model 61|Model 61 slide rifle could be chambered for it, well into 1960.[2] By that time, Smith and Wesson and Ruger had revolvers for it, and Savage had come out with the Model 24, a .22/.410 combination rifle. It was the only successful rimfire cartridge introduced in the 20th Century.[3]
The .22 WMR uses a larger case than the more popular .22 Long Rifle, both in diameter and length. The .22 WMR case is a lengthened version of the older .22 WRF (.22 WRF may be fired in a .22 WMR but not vice versa). The .22 WMR's case is thicker than that of the .22 LR, allowing higher pressures. The combination of more powder and higher pressures gives velocities over 2,000 feet per second (610 m/s) from a rifle using a 30-grain (1.9 g) bullet, and 1,500 feet (460 m) per second (460 m/s) from a handgun. A .22 WMR round will not fit into the chamber of a .22 LR firearm but is possible to chamber and fire .22 LR rounds in a .22 WMR firearm. This is potentially hazardous due to the difference in case diameter. When fired, the .22 LR case expands in the chamber, which can cause the case to split open or become stuck. Also, the long rifle bullet will travel in the magnum chamber unsupported for .4" before entering the barrel causing leading in the chamber.
Since the .22 WMR generally uses the same weight bullets as the .22 Long Rifle, it is generally used in similar situations. The 40-grain (2.6 g) .22 WMR at 100 yards (91 m) still retains the velocity of a .22 LR at the muzzle, which can provide improved penetration at all ranges, and more reliable expansion at longer ranges with expanding bullets.
If sighted in for maximum point blank range on a 3-inch (76 mm) high target, the 40-grain (2.6 g) .22 WMR can reach ranges of nearly 125 yards (114 m). This makes the .22 WMR an effective short to medium range varmint rifle cartridge. The relatively quiet report and negligible recoil also make it a very pleasant round to shoot for extended periods. The .22 WMR can take down small game such as rabbits, groundhogs, prairie dogs, foxes, and even coyotes at close range.
The .22 WMR operates at pressures beyond what normal blowback actions typically handle. It first appeared in the Savage Model 24 combination rifle, followed by Winchester's own Model 61. A number of single-shots and repeaters were offered in .22WMR, and the self-loading Jefferson Model 159.[2] Until the 1990s, most .22 WMR firearms were bolt action rifles. In the 1990s semi-automatic .22 WMR rifles were introduced by Sturm Ruger, Savage, and Marlin, and more recently Remington and Kel-Tec. Revolvers in .22 WMR are made by Taurus, North American Arms, Tanfoglio, Heritage Arms, and Sturm Ruger. The Argentine EDDA submachine gun uses the .22 WMR round. Semi-automatic pistols for this cartridge are (or were) produced by Kel-Tec, Grendel and AMT, the latter two now defunct (AMT has been since resurrected by High Standard). The Grendel, AMT and Kel-Tec designs used specially designed chambers with flutes or gas ports, designed to lubricate the long, thin cartridge with gases from the chamber, overcoming the Blish effect and allowing easy extraction of the cartridge.[4]
The .22WMR is little more than an enlarged, more powerful version of the much earlier .22 WRF[2] (which can also be fired in any weapon chambered for .22WMR).[5] It was for a time the most powerful rimfire round available,[6] and even outperformed the .22 WCF.[7]
While more powerful than the .22 Long Rifle, ammunition is not available in as large a variety as .22 LR. Availability is also not as great, either; while the .22 WMR is by no means hard to find, nearly every retailer that sells ammunition will carry .22 LR. The price of .22 WMR is substantially higher than almost all .22 LR, though it is less expensive than the new .17 Rimfire calibers. Since many of the rifles that chamber the .22 WMR use tubular magazines, bullet noses are generally flat or blunt to allow smooth feeding.[8] Recently, new bullets have emerged from Remington, CCI, and Hornady and have 30 or 33-grain (2.1 g) polymer plastic ballistic tips.[9][10][11]
While a pointed bullet is not going to rest against the primer of the round in front of it (as in a centerfire cartridge), a pointed bullet could still hang on the manufacturer's stamp, which is found in the middle of the base of the cartridge.
Bullets for the .22 WMR are generally unlubricated lead with heavy copper plating, in either solid nose or hollow point style designed for small game hunting or pest control (varmint hunting).
Due to the limited selection of commercial ammunition, the .22 WMR was the case used by a small but dedicated group of wildcatters for handloading high performance rimfire ammunition. Generally these loads would use more aerodynamic pointed bullets, the same type used by .22 caliber centerfire cartridges. While often heavier than standard .22 WMR bullets, the sharp nose and tapered tail retained velocity better, and delivered more energy downrange. Other wildcatters would neck the .22 WMR down to smaller calibers, such as .20 (5 mm) and .17 (4.5 mm) or even smaller, in an attempt to get maximum velocity and the flattest possible trajectory.
The .22 WMR is effective out to 125 yd (115 m) on varmints such as fox or coyote. When loaded with hollow-point bullets, it is too destructive for small game (under 50 yd [45 m]), such as rabbits or prairie dogs or anything intended for eating.[2]
In 2011, Speer released a .22 magnum version of their Gold Dot Personal Protection ammo and Hornady of their Critical Defense ammo.[12] Both are optimized for the short barrels found in self-defense handguns. Both are made for self-defense.