Smith & Wesson Model 66, Combat Magnum, Double Action/Single Action, Metal Frame Revolver, K-Frame, 357 Magnum, 2.75 Barrel, Stainless Steel, Rubber Grip, Red Ramp Front and Adjustable Black Blade Rear Sight, 6 Rounds 10061 The K-Frame revolver is one of the most important innovations in Smith & Wesson history. Since its introduction in 1899, the K-Frame has been a favorite for military and police professionals as well as target shooters and enthusiasts.