Introduced by Winchester in 1930, the .22 Hornet was the first commercial varmint cartridge adopted by a U.S. Manufacturer. The Hornet was developed during the 1920's by wildcatters who loaded the old .22 WCF case with smokeless powders and jacketed bullets. Although the .22 Hornet is far outclassed by more modern cartridges, it will still get the job done out to 200 paces when loaded to maximum chamber pressures in the Winchester Model 70, Sako L64, and Kimber Model 82. In a strong modern rifle, the Hornet will push a 40 grain bullet almost as fast as a 50 grain bullet leaves the muzzle of a .222. However, when loading the Hornet for rifles of lesser strength, it is best to keep velocities in the neighborhood of 2500-2600 fps. Best bullets for shooting varmints with the Hornet are those weighing 40 and 45 grains. It's relatively small powder capacity will not allow this cartridge to push heavier bullets fast enough for the explosive expansion needed for humane kills on larger varmints, especially when the range is extended beyond 100 paces or so. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.