I adhere to the notion that modern mono/partition bullets are simply a bad & risky idea in vintage DR or Combo guns/rifles*.
As John mentions, the mono/partition with raised driving bands maybe not so risky…..but unless forced to comply with the totalitarian “green” diktats, why do it.

Fortunately my vintage rifles (mostly Black Powder Express) are quite happy with cast lead bullets and where I live thus far lead is still permissible, available, and at common DR distances perform just fine. For me then, bullet availability is not an issue. (Not chasing dangerous game)
I feel for the guys with vintage/antique arms that live/hunt in places that insanely require non-lead bullets.
- Mike

ADDED -
Another thought: Being that the this thread was a question by “LGF” as to the suitability of mono/partition in his vintage .470 double rifle I am guessing that not only is there a risk to his barrels, but due to weight/length/internal ballistics issues may arise in simply finding a load using a banded mono or partition that will regulate suitably?
That is what is/was so nice about the Woodleigh bullets, they fairly duplicated the originals by Kynoch.

NOT knocking Swift or any other similar bullet, they are simply great in suitable rifles.

* Note, I am not entirely an unreformed double rifle Luddite as I do have a Nitro .470 as well as a Nitro .500/.450