The .600 Nitro Express Zeliska revolver is an Austrian single-action revolver produced by Pfeifer firearms. Except for the Giant 1859 28mm Remington revolver, the Zeliska may be the largest handgun in the world, weighing in at 6.001 kilograms (13.230 lb) and having a length of 55 centimetres (22 in). The cylinder section alone weighs 2.041 kilograms (4.500 lb). The Zeliska is one of the most powerful handguns in the world, producing a muzzle energy of 7,591 foot pounds. The weight of the handgun helps control the recoil, making controlled shooting possible. The capacity of a Zeliska is five .600 Nitro Express or .458 Win Mag rounds. The Zeliska fires a .600 Nitro Express slug (900 grain) at 1,950 ft/s (594.36 m/s, 2,139.7 km/h). The cost of a Zeliska revolver is $17,316. Each .600 Nitro Express round costs $40, making this gun very expensive to fire.
Loading is accomplished through a loading gate located on the right of the cylinder, similar to the Colt Single Action Army, which the Zeliska is largely based on.
Added features to the gun include gold-plated hammer, cylinder pivot, action and the gold-filled inscription on the gun indicating the company's address.