FANTASY becomes reality !
Just bought Guns & Ammo Jan 2000, and there on page 80 in the 'new for 2000' section is this:
Heavyweight from Hornady: The Heavy Mag H2K shotgun slug features a Hornady 300-grain XTP Mag bullet that will essentially turn your shotgun into a .45-70 rifle. The load comes in 2 3/4 inch persuasion only and boasts a muzzle velocity of 2,664 foot-pounds. The XTP acronym, incidentally, stands for Extreme Terminal Performance, and that appears to be what this item is all about. With a 150 yard zero from a 30-inch barrel, the drop at 200 yards is 6.54 inches.