The great advantages of having a "repeater" over a single barrelled rifle are so obvious, before the invention of true "repeater" rifles.

As has been said above many early DRs were in medium sized calibres for medium sized game.

With more modern bolt action (and other) designs in smaller and medium calibres offering multiple shots, the DR in heavy calibres came into its own where the second shot being instantly available became more important for dangerous game hunting. The reason they are again growing in popularity today with 'relatively' cheaper modern made DRs available to the average 'heeled' hunter.

Still haven't been replaced as an ideal for close fast hunting of running game, with the balance of a shotgun, or for closer action on dangerous game.

JMOs.

Great thread and comments in the thread above.