The K-Frame revolver is one of the most important innovations in Smith & Wesson history and was built specifically to handle the .38 S&W Special cartridge. Since its introduction in 1899, the K-Frame has been a favorite for military and police professionals as well as target shooters and enthusiasts. Today's K-Frame is available in .22 LR and .38 S&W Special. It features a full top strap and barrel serration, Ball-Detent Lock-Up and 2 piece barrel.