9.3X57, The original idea for them appears to have been a shotgun that could fire a slug if required

My own 10 bore Paradox, very early was as such, lightweight with straight hand stock, both shotgun and rifled Ball Gun (posted somewhere here)

when it became clear that they were as accurate as most rifles, lighter and with less recoil, H&H brought out a heavyweight 12 bore that would outperform the 10s, which did then, not sell

The answer was this wonderful Paradox, heavier and more powerful all round
The shotgun issue was irrelevant to the majority of richer hunters, a shotgun for birds as well as a lighter smaller bore rifle being taken on safari

Do not forget that at this time, before Nitro powders, the 8 bore, and now this 10 bore was the standard Dangerous Game rifle, with the mighty 4 bore (or heavyweight 8 bore Paradox, at around 15lbs, more handleable) for close up work
The advent of the .450-.600 Nitro rifles theoretically made them obsolete (although I certainly prefer them myself)

TH44