This is an 8⅜" barreled .44 Magnum.  The Model 29 was offered with 3", 4", 5", 6", 6˝", 8⅜" and, later, 10⅝" barrel lengths as standard models. Other barrel lengths were available either by special order from Smith & Wesson's Custom Shop or custom built by gunsmiths. Finish options available included a highly polished blued or nickel-plated surface.