I have a sxs British Hollis hammer double rifle in .450/400. I love and shoot various sxs double rifles, but also like and shoot o/u double rifles, and feel that an o/u seems more suited to fitting a scope, so when I need a scope, I use an o/u, but otherwise I generally use a sxs. My old friend, the late Elmer Keith, was right when he said that this caliber is perfect for Alaska.