Pancor Jackhammer: The Real One
The Pancor Jackhammer was a select-fire combat shotgun designed by John Andersen in the 1980s. He was a Korean War veteran who had used a pump shotgun in combat, and while he liked the shotgun concept, he felt there must be a more efficient way to make a shotgun than a single-loading pump action. The tinkered with ideas and designs, and ultimately devised the Jackhammer. It is a remarkably clever and interesting mechanism, combining mechanical elements from the Mannlicher 1894, 1895 Nagant revolver, and the Webley-Fosbery automatic revolver.
After making several dozen mockups out of wood and clay to get the mechanics just right, Andersen built a fully functional prototype, which is the gun you see here. It used a lot of large cast parts (and weighed a fully 17.5 pounds), and had a very slow reloading process. However, it proved that the concept was valid and it worked reliably. Andersen then made two more with much lighter materials and a much improved reloading mechanism. These two guns were submitted to the US military for testing, and both were ultimately destroyed by HP White Labs in destructive tests. The testing proved very positive (the guns survived a 50,000 round endurance test), but were ultimately rejected by the military.
The first prototype was kept personally by Andersen, and is now the sole existing Jackhammer. It was owned for several years by Movie Gun Services, which rented it to a number of film, video game, and comic book companies. Because of this and its very distinctive appearance, the Jackhammer has made appearances in a vast number of comics and video games.
https://www.youtube.com/watch?v=-VKGhqIl4Gw
How a Pancor Jackhammer works
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.
The Jackhammer was designed by John A. Anderson, who formed the company Pancor Industries in New Mexico. Reportedly, several foreign governments expressed interest in the design and even ordered initial production units once ready for delivery.[citation needed] However, the design was held up for production due to United States Department of Defense testing, though the design was eventually rejected. With no customers and little interest, Pancor went bankrupt. Supposed overseas orders were subject to United States Department of State approval that was not forthcoming. The assets of Pancor were sold off, including the few prototypes built.
https://www.youtube.com/watch?v=7kzsQOcrvHk
Striker 12: Shotgun Turned "Destructive Device"
The Striker shotgun was designed by a Rhodesian named Hilton Walker in the late 1970s, although not manufactured until after he had emigrated to South Africa. He partnered with the owner of the Armsel company to finance production, which was actually done by a company called Aserma Manufacturing. The original Striker version of the gun used a wind-up spring-powered 12-round cylinder coupled with a gas auto-ejection system for all but the final round fired. This was treated as a semiautomatic shotgun by the South African police, and Walker redesigned it in 1991 to be manually indexed (by pivoting the front grip and barrel shroud between shots). This allowed for less regulated sale in South Africa at the time.
For the export market - like the United States - the distinction was not relevant, and it was the Striker model with its wind-up cylinder that was brought in by a company called Sentinel Arms. Both a full-length version with an 18 inch barrel and folding stock, and an “entry” version with a 7 inch barrel and no stock, were sold. In 1994, public pressure led the Clinton administration to designate the Striker-12 along with the Cobray Streetsweeper and USAS-12 shotguns as Destructive Devices under the 1934 National Firearms Act. This was legally possible because the NFA considers all firearms with bore diameters over 1/2 inch to be Destructive Devices, with guns like shotguns exempted if they are considered suitable for sporting purposes.
https://www.youtube.com/watch?v=RlR1CI3ck_U
In terms of efficiency, semi automatic with a box magazine; you probably could make it bull pup.
And automatic.
