Obviously your intended hunting revolver and load need to be reasonably accurate, but often it boils down to the shooter. I have a couple of revolvers in big calibers (.475 Linebaugh, .500 JRH, etc.) that are capable of shooting well under an inch at 50 yards. But all of that is academic as in the field you don't often have a good rest and certainly no sandbags. I practice a lot offhand out to about 100 yards and it has made me a much better shot all around. I do think 2-inches at 50 yards is more than acceptable. Work your loads to the most accurate possible and then practice, practice, practice. And then practice some more......
