It would seem that the choosing of a 450/400 Double or other DR in kind for the primary rifle would depend on the ability of the Double to hit out to 200 yds with a scope off a shooting stick or other assitance.

I feel the advantages of a Double to hit at a distance with a rapid 2nd shot without changing ones grip is considerable vs a big bolt.The option to choose solid or soft is attractive as well as the QD scope feature.

Is a 450/400 or similar DR accurate at 200 yds? I don't have one so I don't know.If not then the most sensible alternative would seem to be whatever big bolt the hunter shoots well.