mbogo
You did not say which double rifle you are buying.
If you are buying a new made double I would get a 470.
However if you are considering an original British Double then Ingwe has given you good advise. Either of the 450/400's are most excellent, especially in a rifle under 10 lbs. I have a 450/400 3 1/4" that weighs 9 1/4 lbs and I like it very much. I have had excellent results on deer and pigs with 300 grain Hawk bullets, and I have taken 2 caribou
and a black bear with 400grain Woodleigh Softs.
It has quite a bit less recoil than a 470 or my 450 No2. My 450 No2 weighs 11 3/4 lbs and can get heavy in rough country, like hunting Zimbabwe mountain elephants. I have carried the 450/400 on backpacking hunts in Montana and for 45 days of hunting in Alaska.
Before you buy, take a look at some British 450/400's.
If I could have only ONE hunting rifle I would scope my 450/400. With 300grain bullets at @ 2335 fps and 400grain Woodleigh Softs and Solids at @2150 fps, I could hunt anything on the planet.