As evidenced by its substantial IMFDB page, the Pancor Jackhammer has been a popular inclusion in many popular video games. What’s interesting about this is that the Jackhammer, otherwise, would be an extremely obscure firearm. Only three were made, and of those three, only the initial proof-of-concept prototype exists today. Ian of Forgotten Weapons has gotten a rare chance to take a look at this last Pancor shotgun, which he shares with us in a recent video:

Virtually everything I know about the Pancor Jackhammer is repeated in the video above. Ian’s overview may be the most comprehensive publicly available treatise on the gun, which is unsurprising given its rarity. Essentially, the Jackhammer is a forward-moving-barrel gas operated weapon with a Webley-Fosbery-style rotating revolver cylinder and a Nagant-revolver-esque chamber seal, chambered for 12 gauge and fully-automatic. Ian thoroughly describes the weapon’s operation (which is, so far as I know, utterly unique) in the video above, but essentially gas is tapped from two ports in the barrel, forcing it to move forward and disengage from a matching recess in the indexed chamber face. As it does this, a connecting rod causes the cylinder to rotate in a manner analogous to a Webley-Fosbery, and the striker is cocked. The barrel returns to battery via its spring and the chamber rotates the rest of the way back into position, where the barrel seats itself in the next chamber.