The Jackhammer was designed in 1984 by John A. Anderson, founder of Pancor Industries, which was based out of New Mexico. Apparently, there were several foreign governments that were interested in the design, even going so far as to order initial production units once they had been readied for shipping. The design was held up for production due to testing by the US Department of Defense and it was eventually rejected. With no customers and little interest in the design, Pancor Industries soon went bankrupt, and all of their assets were sold off, including the prototypes that had been constructed.
The Jackhammer had a fire rate of 240 rounds per minute, and weighed 4.57 kilograms. It had a length of 78.7 centimetres, with a barrel length of 52.5 centimetres. The weapon's method of rotation utilised an operating rod to rotate the cylinder, a method also used by the Webley-Fosbery semi-automatic revolver. The Jackhammer was also classified as a machine gun under the National Firearms Act of 1934.
- Very high rate of fire for a shotgun (240 rounds per minute).
- Last model in existence can fire standard 12-gauge cartridges
- No functional models exist, except for a semi-finished toolroom prototype.
- No functional cylinders exist.
- Very high rate of fire leads to ammo depletion.
- Small magazine size for an automatic weapon (10 rounds).