The Smith & Wesson 4506 is a third generation semi-auto single action/double action pistol chambered in .45 ACP, with an 8 round magazine. The 4506 is chambered for the .45 ACP cartridge and, with the purchase of special springs, the stronger .45 Super. It is constructed almost entirely from stainless steel and is thus extremely resistant to harsh weather conditions. The 4506 is a traditional double-action/single-action pistol. The first shot is fired in double action mode. Each subsequent shot is fired single action mode. It features one-piece Xenoy wrap-around grips with either a curved or straight back strap. The 4506 was produced from 1988 to 1999.
Domingo Gallardo "Krazy 8" Molina uses a S&W 4506 in the pilot episode. Not long after, Walt becomes its new owner before Jesse finally disposes of it in the following episode.