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A Brief History of .22 Rimfire Ammunition
By Chuck Hawks
The rimfire principle was used to create the first successful self-contained metallic ammunition. Rimfire cases are constructed with the priming compound spun inside the rim of the copper or brass case, which is crushed by the blow of the firing pin to ignite the main powder charge.
The first rimfire cartridges were .22s, but after the type became established many larger caliber rimfire cartridges were developed in the mid to late 19th Century. Some of these had a good run of popularity until they were superceded by the development of higher pressure centerfire ammunition.
Calibers ranged from the .25 Short to the .58 Miller. Probably the best known of the larger caliber rimfires are the .25 Stevens, .32 Long, and .44 Henry Flat. The latter was the cartridge for which the seminal Henry and Winchester 1866 "Yellow Boy" lever action rifles were chambered.
Guns and ammunition for the last of the larger caliber rimfires was discontinued in the U.S. in the late 1930's and early 1940's. According to Cartridges of the World by Frank C. Barnes/Edited by M.L. McPherson, for which I am indebted for much of the historical information in this article, Navy Arms commissioned a run of .32 Long ammunition from a Brazilian manufacturer in 1990.
In addition to the larger caliber rimfire cartridges of the past, in recent times sub-caliber rimfire cartridges have been introduced. Among these are the 5mm Remington Magnum, .17 Mach 2, the very successful .17 HMR and the .17 WSM. However, the focus of this article is .22 caliber rimfire cartridges.
All .22 rimfires (except the WRF and WMR) are ancient black powder designs and use tapered heel bullets. If you examine a .22 S, L, or LR cartridge you will see that the case and bullet are the same diameter. The part of the bullet inside of the case (the heel) is reduced in diameter to allow it to fit inside of the case. Such bullets are also called "outside lubricated," because they are ordinarily waxed or copper plated. In all other modern cartridges, the bullet shank is of constant diameter and the case is slightly larger than the bullet to allow the heel of the latter to fit inside. This old fashioned term for this design is "inside lubricated," as the lubrication grooves of lead bullets are inside of the case.
The BB Cap was the first type of rimfire ammunition. BB stands for "bullet breech." It was invented in France around 1845, designed for the Flobert indoor target rifle. BB Caps were designed for shooting gallery use and are seldom encountered these days, as shooting galleries are now considered politically incorrect by socialists, tort lawyers, girly men, and liberal politicians.
The BB Cap fires a round lead projectile (ball) powered only by the priming compound in the rim of the case, which is very short as no powder is used. The case is just there to hold the priming compound and bullet together.
BB Caps were made in Europe and America until fairly recently. The last I saw were made in Germany by RWS who, I believe, still loads them today.
The successor to the BB Cap was the CB Cap. "CB" stands for "Conical Bullet." The CB cap uses a 29 grain round nose lead bullet and a tiny pinch of powder. This is also shooting gallery ammunition. CCI produces modern CB Cap loads in .22 Short and .22 Long cases (firearms chambered for the Long Rifle cartridge being far more common today) for gallery and indoor practice use. The MV of either is 710 fps.
The common .22 Short cartridge dates from 1857. It is the oldest cartridge still being loaded today. It was the first American metallic cartridge, introduced in for the first S&W revolver, a pocket pistol developed for personal protection. It was popular during the American Civil War, carried as personal weapons by soldiers on both sides.
The .22 Short is a development of the BB cap using a 29 grain round nose (RN) bullet in a lengthened case (compared to the BB Cap). It was originally powered by 4 grains of fine black powder (about FFFFg). After the advent of smokeless powder, the .22 short was adapted to the new, cleaner burning propellant. Although no longer extremely popular, it is still used all over the world and in the Olympic games for the rapid fire pistol event. Modern .22 Short High Velocity ammunition is loaded to a MV of approximately 1095 fps and ME of 77 ft. lbs. from a rifle barrel (Remington figures).
The .22 Short is a pretty anemic round, and in 1871 a longer case of the same diameter was developed for the 29 grain Short bullet. This became the .22 Long cartridge, still occasionally seen (but obsolescent) today. The .22 Long was once chambered in a large number of pistols and rifles. It was originally loaded with 5.0 grains of very fine black powder and offered about 100+ fps greater velocity than the .22 Short. The Long survived the change to smokeless powder and is still occasionally seen today. CCI loads their .22 Long High Velocity ammo to a MV of 1215 fps and ME of 95 ft. lbs.
Around 1880 the .22 Extra Long cartridge appeared, powered by 6.0 grains of black powder. It fired a 40 grain tapered heel bullet (the same as the later .22 Long Rifle) at a MV similar to the Long Rifle, but used a longer case than the .22 LR. This cartridge was available in a number of rifles in the late 19th Century. .22 Extra Long ammunition was finally discontinued around 1935.
In 1887 the Stevens Arms Co. developed the ultimate in .22 rimfire cartridges, the .22 Long Rifle. This used the .22 Long case with a 40 grain RN bullet loaded to higher velocity than the 29 grain Long bullet. It shot flatter and hit harder than any of the previous .22 rimfires except the .22 Extra Long, whose performance it essentially duplicated in a shorter case, and it was more accurate than that cartridge.
The .22 Long Rifle caught on, was adapted to both rifles and pistols, and became the most popular sporting and target shooting cartridge in the world. After the advent of smokeless powder a High Velocity version of the .22 LR was introduced, which further extended the .22 LR's superiority as a small game hunting cartridge.
Modern .22 LR target ammunition is loaded to a MV of about 1085 fps with a 40 grain RN bullet. .22 Long Rifle High Velocity cartridges drive a 40 grain copper-plated bullet at a MV of 1255 fps and ME of 140 ft. lbs. from a rifle barrel. For small game hunters, most manufacturers offer a 36-37 grain copper-plated lead hollow point bullet at about 1280 fps (Remington figures). This load expands nicely and makes for quick kills on small game, given proper bullet placement.
Because of its popularity there are many permutations of the .22 LR cartridge. One of the least common is the .22 LR shot cartridge, which fires a pinch of very fine #12 ("dust") shot. This load is used, among other things, to collect very small creatures, mice and the like, for museum displays when fired from smooth bore barrels.
Far more useful are the Hyper Velocity .22 LR loads pioneered by CCI in the form of the Stinger. These use lightweight hollow point bullets at increased velocity for flatter trajectory and dramatic expansion. Remington followed suit with their famous Yellow Jacket load, and the idea was subsequently picked-up by most other manufacturers. The CCI Stinger drives a 32 grain GLHP bullet at a MV of 1640 fps with 191 ft. lbs. of ME.
In 1890 the .22 Winchester Rim Fire (WRF) was introduced. This cartridge is loaded with a 45 grain, flat point, inside lubricated bullet with a full diameter heel, rather than the tapered heel bullet of the .22 LR. The .22 WRF fires a .224" diameter bullet, just like modern centerfire .22s and the later .22 Magnum (WMR). At one time a 40 grain HP bullet was also available, but it has since fallen by the wayside.
Remington called this cartridge the .22 Remington Special, and loaded it with a 45 grain RN bullet. The .22 Rem. Spec. and .22 WRF are the same cartridge and are interchangeable.
The .22 WRF is a good small game cartridge, superior to the .22 LR. CCI loads the ammunition, and Winchester does an occasional run of .22 WRF. Modern CCI ammo is loaded to a MV of 1300 fps and ME of 169 ft. lbs.
Today the .22 WRF is kept alive primarily as a less destructive small game load for rifles chambered for the .22 WMR cartridge. The .22 Magnum is a lengthened version of the .22 WRF and will chamber in firearms designed for the .22 WMR, much as .38 Special ammunition may be fired from .357 Magnum guns, although it will not function correctly in autoloaders.
In the early 20th Century a pair of cartridges about the same size and offering about the same ballistics as the .22 LR were introduced. These were designed for use in autoloading rifles, used smokeless powder and inside lubricated bullets, and in that respect are a more modern design than the .22 LR. However, as soon as the established .22 LR was universally converted to smokeless powder, the .22 Auto cartridges became superfluous.
The .22 Winchester Automatic cartridge was designed for their Model 1903 autoloading rifle (discontinued in 1932). Ammo was produced into the 1970's. Remington's .22 Automatic appeared in their Model 16 autoloader. That rifle was discontinued in 1928, and the ammunition was not loaded after the Second World War. Although similar, these two cartridges differ dimensionally and are not interchangeable.
Jump to 1959, the year Winchester introduced their very successful .22 Winchester Magnum Rimfire (WMR). This cartridge pushes the limits of pressure possible with a rimfire case given the limits of contemporary metallurgy. The .22 Magnum was initially offered with 40 grain FMJ and JHP bullets at an advertised MV of 2000 fps from a rifle barrel and 1550 fps from a pistol barrel. Due to its high velocity, .22 WMR cartridges are loaded with jacketed bullets.
The .22 WMR is based on a lengthened version of the .22 WRF case, like that cartridge uses standard diameter .224" inside lubricated bullets, and remains to this day the most powerful .22 rimfire cartridge ever. It has been adapted to many types and brands of firearms, and .22 WMR ammunition is loaded by all of the major rimfire ammunition manufacturers and is very widely distributed.
As good as the .22 WMR is as a rifle cartridge, I feel that it is even better as a revolver cartridge. It offers velocity and trajectory similar to the centerfire magnum pistol cartridges at a fraction of the recoil and cost. Convertible revolvers, supplied with both .22 LR and .22 WMR cylinders, are the ultimate in versatility for plinking, small game hunting, and varmint shooting.
Today the .22 WMR is available with bullet weights ranging from about 30 to 50 grains, and CCI loads a shot shell version. The standard Winchester 40 grain JHP bullet is now loaded to a rifle MV of 1910 fps with ME of 324 ft. lbs. The various 30-40 grain JHP bullets are best for varmint hunting, but are overly destructive on small game intended for the dinner table. A better choice in that case are the heavier 45-50 grain bullets intended for small game hunting, or the use of .22 WRF ammo when possible.
The .22 WMR is the newest, commercially successful, .22 rimfire cartridge (so far). With .22 rimfire cartridges now available from the BB Cap to the WMR, the field seems pretty well covered. Recent rimfire development has concentrated on lighter, smaller caliber bullets that can achieve higher velocity within the existing pressure limits. The .17 HMR, based on a necked-down .22 Magnum case, is the best example.
Rimfire cartridge design is limited by the fact that the brass case rim must be weak enough to be crushed by the blow of the firing pin. This severely limits the permissible maximum pressure and thus the performance of the cartridge. I suspect that the advent of more potent .22 rimfire cartridges will depend on the future development of more advanced case materials.
Copyright 2005, 2014 by Chuck Hawks. All rights reserved.