MK4A1

The Pancor Corporation Jackhammer was a 12-gauge, gas-operated automatic shotgun designed in 1984 and patented in 1987. Only a few working prototypes of the Jackhammer were built. In the late 1990s, the current owner of the design, Mark III, attempted to sell the patents, prototypes, and production rights for $350,000. Nonetheless, its distinctive appearance and futuristic design have made it a prop in action films, television programs, and video games.

Though unconventional, the Jackhammer can best be described as a gas-operated revolver. Many parts were constructed of rynite polymer to reduce weight. Layout was of a bullpup configuration with a 525 mm barrel and an overall 787 mm long firearm. The shotgun used a 10-round revolving cylinder and fired conventional, 12-gauge shells. Weight was 4.57 kg and maximum rate of fire was 240 rpm. The cylinder's method of rotation was very similar to the Webley-Fosbery Semi-automatic revolver, an operating rod being used to rotate the cylinder.

At the moment of firing, the front of the shell sealed inside the breech of the barrel much like the Nagant M1895 revolver. Unlike the Nagant whose cylinder moved forward to form the seal, the barrel of the Jackhammer was driven forward and away from the cylinder by a ring-piston using gas tapped from the bore. As the barrel moved forward, the breech cleared the front of the fired cartridge and an operating rod attached to the barrel rotated the cylinder through a "zig-zag" cam arrangement. As the next shell aligned with the bore, the barrel returned under spring pressure. Spent shells were retained in the cylinder, as in a traditional revolver. For reloading, the cylinder was removed from the bottom of its housing and shells were manually extracted.

The Mark 4 A1 variant of Jackhammer is brand new variant designed by Magnum in 2013. It was completely redisigned heir apparent to the original but has addressed the flaws of the original model.

Section heading
Write the first section of your page here.