LGF, you might want to consider these slugs
http://www.ada.ru/Guns/hunting/slugs/rubeykina/index.htm Sorry, the text is Russian, but what you need are the blueprints anyway. The dimensions are in millimeters (you need the top right-hand pic).
These bullets are all brass, made on a lathe, a do-it-yourself kind. They are loaded in a plastic shot cup, which protects the bore along with the fact that these slugs are way underbore. They were used on bear and moose when sproting rifles in the USSR were illegal, and always produced excellent killing power with very deep penetration. For the "last resort" cartridge you can load'em up. A solid weighting 33 gramms and leaving the muzzle at 450 meters per second is an equivelent of the 12 bore rifle, which if the books I read were the right kind, used to be a reliable short-range killer of the Big Five in its time.
