Bore or gauge rifles are simply a rifle whose case and bore are measured in terms of shotgun gauge 20,12,10etc. "Paradox" style guns were designed to shoot both conical ball and shot. They could shoot further and with a heavier conical bullet than a roundball gun and with some choke in the shot patterning. Paradox guns weigh less than a fully rifled gun but only slightly more than a shotgun.
There were a number of systems used by various makers to achieve the balance between bullet stabilization and shot patterning , invisible rifling, oval boring but the most effective was the Fosbury paradox rifled choke system used by Holland and later by most other makers. The standard 12 bore conical would have been about 740grs. The big bore paradoxes are true dangerous game guns and give away nothing but a little recoil when compared to their fully rifled counterparts.