I have made no secret how I feel about double rifles and their use in North America. I think the double rifle in the proper caliber is the BEST hunting rifle for ALL game that is hunted and shot at distances under 200 yards.
I have used 3 different doubles in NA.
1. A Chapuis 9,3x74R with a 2.5x8 Leupold in QD mounts.
2. A British 450/400 3 1/4" weight 9 1/4 lbs
3. A British 450 No2 weight 11 3/4 lbs
This is the short version, I can furnish more info on request.
The 9,3 with the scope is a great hunting rifle for all NA game from deer [not to powerful] to Big Bear [enough power].
The scope makes it the equal of the 375 H&H out to 200 yards. [I haven't shot the 9,3 farther]
It has become one of my most favorite rifles.

The 450/400 is the perfect big bore double for NA. Plenty of power and penetration for Big Bears, also good for Moose and Elk. The range factor with iron sights is a consideration. A scope on the 450/400 would make it the equal of any of the 40 cal bolt rifles out to 200 yards for sure. Some day I may scope the 400 double.

3. The 450 No2. I have used this rifle a lot on my lease for deer and pigs, and on an Eland at Camp Cooley in preparation for Africa. This is my favorite rifle of all time, it fits me better than any other rifle I have shot. However it is just too heavy for "rough country" hunting. When I hunted in Montana I used the 450/400 and the 9,3. I have taken the 400 to Alaska twice. I did take the 450 No2 to Idaho for Black Bear over bait [also had the 9,3 and would switch out every couple of days, shot the bear with the 9,3], I would not want to carry it long distances in "rough country".
The 400 is lighter and has all the power needed for NA. Even Elmer Keith felt the same way about big bore doubles.

I think I have the perfect trio of double rifles...
But since I like even numbers I lust for a 577 3" Nitro

Don't need one, just want one.