Remington’s hunting AR-15, the R-15, is now available chambered in .450 Bushmaster. The gun features an 18″ free-floading and fluted barrel and Mossy Oak Break-Up camo finish. The magazine can hold four rounds of the large .450 Bushmaster.
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. ]