Gun Manufacturers Smith & Wesson have unleashed their newest revolver: a monster .460 calibre handgun which they say is 'great for a back-up gun, or for hunting'. Named the 'Backpack Cannon', the gun was unveiled in Las Vegas on Monday at the Shooting, Hunting, and Outdoor Trade show, the largest gun show in the U.S., which around 60,000 gun fans attend every year. The cannon features a three-inch barrel, high visibility sights and synthetic shock absorber on the rear of the handle, as well as a massive chamber to fit the gigantic .460 calibre rounds, which are some of the...