Lancaster, who manufactured four barrel rifles, pistols, and shotguns, produced this .440 bore or 28 gauge piece offering double the firepower of a standard side-by-side. Charles Lancaster started as a barrel maker in Londons Drury Lane in 1811, producing barrels for Joseph Manton and others. By 1826, his firm had moved to 151 New Bond Street and had received a royal appointment to Albert the Prince Consort.
. This is the ultimate Zombie Killing tool. 5.56 is easily scavangeable from civilian and military sources, it has enough penetration value to put a round through a skull and the under-slung shotgun is an excellent close-quarter backup weapon with a completely separate firing mechanism in case the AR jams. - http://www.RGrips.com
X -Caliber® is designed for use in any condition and with any ammunition available. up to 12 different calibers thanks to the 8 steel adapters supplied. In addition to the two original gauges, adapters allow you to shoot 8 pistol calibers ( .380 , 9 mm , .357Mag/.38SP , .40 S W, .44 Mag, .45 ACP , .410/.45colt ) and two shotgun calibers (410 ga, 20ga), combining the flexibility of a shotgun and the power of a rifled gun. http://www.chiappafirearms.com/product/2677