The Ruger SR22 is an American made .22 calibre pistol produced by Sturm, Ruger & Co. of Southport, Conneticut. The SR22 was released in 2012, adding to Ruger's established range of .22 calibre pistols, with ergonomic design at its heart.
The SR22 was released in 2012, and resembles the Walther P22, although the SR22 is only three quarters of the size. The SR22, unlike Ruger's other .22 pistols, such as the Mark III, is designed as an all rounder, open to various potential markets such as hunting. The SR22 is also able to use the most potent forms of the .22 Long Rifle cartridge, while being one of the lightest pistols made by Ruger.
As is increasingly common for .22 pistols, the SR22 is manufactured from polymer and aluminium, with the frame set in polymer and the slide manufactured from aluminium. This means that the SR22 only weighs 1.1lb (0.49kg), lighter than their other lightweight pistols such as the 22/45. The use of polymer also means that an ergonomic grip can be made to better fit the shooter's hand, while also making the SR22 ambidextrous (with both a grip safety and magazine release on either side of the frame.
The SR22 is manufactured with a picatinny rail, located under the barrel (and infront of the trigger guard) allowing aftermarket attachments to be added. It can also be ordered with a threaded barrel for muzzle attachments such as silencers, as well as a choice of finishes for the slide (anodised black or silver). The barrel, manufactured from stainless steel to avoid corrosion, is replaceable, as are the polymer grips which attach to the frame.
The SR22, as the name eludes to, is chambered to accept the .22 Long Rifle cartridge, one of the most popular target pistol calibres. These rounds are shot from a ten round magazine, which slots into the grip. New SR22s are sold with two extra magazines as standard.
Image origin: http://www.ruger.com/products/sr22Pistol/models.html