The .22 Hornet or 5.6×35mmR is a varmint, 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 of the .17 HMR bullet. 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.
Left to right: a .22 Short, .22 LR, .22 Winchester Magnum, and a .22 Hornet with Hornady 35 gr (2.3 g) VMax bullet
|Place of origin||United States|
|Wars||World War II|
|Designer||Townsend Whelen / G. L. Wotkyns|
|Variants||.22 Hornet Ackley, .22 K-Hornet|
|Bullet diameter||.224 in (5.7 mm)|
|Neck diameter||.243 in (6.2 mm)|
|Shoulder diameter||.276 in (7.0 mm)|
|Base diameter||.298 in (7.6 mm)|
|Rim diameter||.350 in (8.9 mm)|
|Rim thickness||.065 in (1.7 mm)|
|Case length||1.403 in (35.6 mm)|
|Primer type||small rifle|
|Test barrel length: 24 inches|
Source(s): Hodgdon Powder Company
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 Single Shot 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 (designed by Lysle Kilbourn) and .22 Ackley Improved 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 legal for deer in some other countries 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. The United States being the only exception to a complete prohibition of the use of expanding bullets in war, due to its ambiguous policy.  However, the cartridges 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.
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.
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 Center Arms. Muzzle velocities are somewhat less for this cartridge in short-barreled handguns than in rifles.
- ".22 Hornet load data at Hodgdon". Archived from the original on 2007-11-16. Retrieved 2007-07-14.
- Barnes, Frank C. (1997) . McPherson, M.L. (ed.). Cartridges of the World (8th ed.). DBI Books. p. 16. ISBN 0-87349-178-5.
- American Rifleman. National Rifle Association of America. 1906. p. 509.
- "Deer licences - GOV.UK". Naturalengland.org.uk. Retrieved 2015-07-04.
- "Customary IHL - Rule 77. Expanding Bullets". ihl-databases.icrc.org. Retrieved 2019-05-15.
- .22 Hornet article at the Reload Bench[self-published source]
- Women and Guns. Little River Press. 2002. p. 51.
- "Survival Guns". Janus Press. 1987.
- "The .22 Hornet". gunsmagazine.com. Archived from the original on 2016-12-15. Retrieved 2015-12-27.
- Field & Stream. November 1989. pp. 52–. ISSN 8755-8599.
- Ben McC. Moïse (28 July 2014). A Southern Sportsman: The Hunting Memoirs of Henry Edwards Davis. University of South Carolina Press. pp. 168–. ISBN 978-1-61117-357-4.
- "Osceola Turkey | Big Game Hunting Records - Safari Club International Online Record Book". Scirecordbook.org. 1999-01-01. Retrieved 2015-07-04.
- "Bullberry Barrel Works - Kinney's Record Osceola Turkey". Bullberry.com. Archived from the original on 2015-07-03. Retrieved 2015-07-04.
- Reg Darling (April 2005). Coyote Soul, Raven Heart: Meditations of a Hunter-wanderer. iUniverse. pp. 37–. ISBN 978-0-595-34977-7.
Although the .22 Hornet is legal for deer hunting in Pennsylvania, calling it marginal is rather an understatement.
- Jack O'Connor (1952). The big-game rifle. Knopf. p. 123.
- Mike McConnell (6 January 2002). Bear Tales and Deer Trails. iUniverse. pp. 217–. ISBN 978-1-4697-1881-1.
- Jack O'Connor (1 January 1977). The Art of Hunting Big Game in North America. Outdoor Life. p. 205. ISBN 978-0-394-41119-4.
- Constance Helmericks (1952). The Flight of the Arctic Tern. Little, Brown. p. 220.
- Richard L. Knight (7 November 2008). Conservation for a New Generation: Redefining Natural Resources Management. Island Press. pp. 221–. ISBN 978-1-59726-921-6.