The .22 Hornet or 5.6×35mmR is a vermin, small-game, predator, and competition centerfire rifle cartridge commercially introduced in 1930. It is considerably more powerful than the .22 WMR and the .17 HMR, achieving higher velocity with a bullet twice the weight. The Hornet also differs very significantly from these in that it is not a rimfire but a centerfire cartridge. This makes it handloadable and reloadable, and thus much more versatile. It was the smallest commercially available .22 caliber centerfire cartridge until the introduction of the FN 5.7×28mm.
The .22 Hornet fills the gap between such popular varmint/predator cartridges as the .22 WMR and the .223 Remington. In regard to muzzle velocity, muzzle energy and noise, it is well suited to vermin and predator control in relatively built-up areas.
Prior to the development of the modern .22 Hornet, there was a conceptually similar but physically different cartridge by the same name invented in the 1890s by Reuben Harwood (nicknamed "Iron Ramrod)", sometimes called the ".22 Harwood Hornet" to avoid confusion, as the two rounds are not compatible. Harwood's cartridge was formed by necking down .25-20 Winchester brass to .22 caliber, and was initially loaded with black powder.
The modern .22 Hornet's ancestry is generally attributed to experiments done in the 1920s using the black-powder .22 WCF at Springfield Armory. Winchester adopted what had so far been a wildcat cartridge in 1930, producing ammo for a cartridge for which no commercially made guns yet had been built. It was not until 1932 that any company began selling commercially made guns for the cartridge.
Wildcat variants of the .22 Hornet, such as the .22 K-Hornet, can boost bullet velocity and energy considerably above factory .22 Hornet levels, but performance still falls short of what is deer-legal in the Netherlands or the United Kingdom, although it is perfectly legal for deer in other countries such as New Zealand, and some American states.
Factory ammunition is widely available from all major manufacturers, generally with bullets weighing 34, 35, 45, or 46 grains (2.2, 2.3, 2.9, or 3.0 g), with bullets invariably either hollow point or soft point. Muzzle velocity typically is in the 2,500 to 3,100 ft/s (760 to 940 m/s) range, and muzzle energy is just over 700 ft·lbf (950 J) for factory ammo fired from a rifle. (Velocities and energies are less when Hornet ammunition is fired from short-barreled firearms.)
Published handload data from major handloading-product companies shows how versatile the .22 Hornet can be. According to the Hodgdon Powder Company reloading data, the heavier bullets show a serious affinity for Lil'Gun smokeless powder to produce much higher velocities than other powder with heavy bullets in this small case.
Beginning during World War II, aircrew survival rifles in .22 Hornet were developed and issued by the U.S. military. They were a bolt-action rifle with adjustable stock (M4 Survival Rifle), a break-open rifle/shotgun over-under (M6 Aircrew Survival Weapon), and a takedown bolt-action rifle (AR-5/MA-1). Military survival issue .22 Hornet ammunition was loaded with soft-point expanding jacketed bullets, not complying with the Hague Convention. However, they were labeled "Under no circumstances is the ammunition to be used for offensive or defensive measures against enemy personnel. This ammunition is provided for use with your emergency survival Rifle for the Killing of Game for food under emergency survival conditions only." It was later determined by the USAF that exigent circumstances and self defense would have exempted soft point ammunition from that provision.
The .22 Hornet is a popular cartridge for the Field/Hunter's pistol category in IHMSA and NRA metallic silhouette shooting.
Survivalist Mel Tappan on the .22 Hornet: "It is accurate, has virtually no recoil and a light report.... [I]ts performance limits its use to small game and pests within 150 or 175 yards. It is by no means a reliable deer cartridge, even with handloads."
Sam Fadala of GUNS magazine calls it "perfect for mid-range varmints of all stripes," everything from small game, mountain birds (e.g., blue grouse), turkey, javelina, peccaries, coyote, and Australian wild pigs and goats.
The Hornet is considered an optimal cartridge for turkey hunting, though it is not as powerful as modern .22 centerfires. At mid-century, southern sportsman Henry Edwards Davis pronounced the Winchester Model 70 chambered for the Hornet "the best commercial rifle for wild turkeys the world has ever seen". In 2011, Lane Kinney was awarded the "Top Turkey in the World" award by Safari Club International for a record-setting Osceola turkey taken with a T/C Contender pistol in .22 Hornet.
The Hornet's virtual absence of recoil has made it even quite popular among deer hunters in some areas, although it is generally regarded as very underpowered for deer unless bullet placement is absolutely precise. American hunter Jack O'Connor decried this practice in the 1950s, stating the Hornet could "under no circumstances" be considered a deer cartridge. Many jurisdictions such as the Netherlands, the UK (Other than England and Wales) and some states in the USA currently prohibit the Hornet (and other .22 caliber cartridges) for use on deer.
The .22 Hornet also proved popular among the Alaskan Inuit due to low cost, who used it for hunting seals, caribou, and even polar bears.
Rifles are currently (2007) being chambered in .22 Hornet by Ruger, New England Firearms, CZ and various other mass-market manufacturers. Most current-production rifles in .22 Hornet are either bolt-action or single-shot designs, with the exception of a very few "survival" rifle/shotgun over-under designs such as the Savage Model 24 from Savage and a few European-made kipplauf break-action, single-shot rifles. Older guns generally have a slower twist rate of 1-16" (or one turn in every 16 inches (410 mm) of barrel length) for lighter bullets with a .223 caliber dimension. Newer guns feature a faster 1-14" twist in the .224 bore diameter.
Revolvers have been produced in .22 Hornet by Taurus, Magnum Research, and others. Single-shot pistols in .22 Hornet have been made by Thompson. (Power levels are somewhat less for this cartridge in short-barreled handguns than in rifles.)