The rifle is pretty much the modern version of the classic .45-70 lever action carbine. A .450 Bushy packs about as much punch as a standard pressure (smokeless) .45-70 round. More than enough power for any North American game.

[ Many thanks to Heath for the info. ]

I found that several people have expressed an interest in obtaining a bolt action rifle in 45-70 caliber, most commonly done by converting a Siamese Mauser or P-14 Enfield. Many have suggested

instead getting a 458 Winchester magnum and loading it down, or using the 458 X 2″ wildcat. Now the 450 Marlin is available, and any bolt action with a H&H magnum bolt face can ve easily adopted to it.

An interesting discussion @ rec.guns.