Would recommend considering Swift A-frames or Northfork bullets rather than Barnes in a Double.
I think top experts JJ or Ken will tell you Monolith bullets are hard on double rifles. I know you will see lots of posts here to the contrary but, take their advice and only use if other premium bullets won't regulate. JJ has more experience with Chapuis doubles than anyone in the US and I take his advice to heart. Copper fouling is an issue and at DR velocities they often don't have reliable expansion.
To those who love Barnes bullets, I apologies to you as most readers her know my feeling on them.
Owning several DR including Heyms and Chapuis I personally have seen and experienced Barnes bullet issues.
Let the HATE MAIL begin!