Pancor Jackhammer

The Pancor Corporation Jackhammer is a combat shotgun. It is a 12 gauge, gas-operated automatic weapon. A stylish design it is one of very few fully automatic shotguns. Patented in 1987 it has not entered full scale production, although its distinctive appearance has made it popular in violent television programs, films and computer games.

The weapon, excluding the barrel, is largely plastic (rynite) construction to reduce weight, with a bullpup layout to preserve barrel length in an overall 787 mm. The gun is fed by a 10 round capacity center-rotating drum using conventional 18.5 × 76 mm cartridges. The gun weighs 4.57 kg and has a maximum rate of fire of 240 rpm.

The firing mechanism is close to that of the Webley-Fosbery automatic revolver. The floating barrel is driven forward by gas pressure from the fired round. It is returned by a spring and moves the drum operating rod, breaking the tight seal between the barrel and the drum and allowing the drum to revolve to offer the the next round. On the return stroke the barrel and drum are resealed allowing the round to be fired without loss of gas. Spent cratridges are not ejected, remaining in the magazine.