S&W Centennial is a family of revolvers made by Smith & Wesson on the "J-Frame". Depending upon caliber, the cylinder holds either 5 (9x19mm Parabellum, .38 Special +P, and .357 Magnum), 6 (.32 H&R Magnum), 7 (.22 Magnum), or 8 (.22 LR) cartridges. Centennials feature a fully enclosed (internal) hammer, which makes them Double Action Only (DAO) firearms. Like all other "J-frame" Smith & Wesson revolvers, they have a swing-out cylinder. Centennial models have been made in different versions like PD "Personal Defense", LS "Lady Smith", and M&P "Military & Police"