I remember reading on Wild West Guns site a while back that when they bore the chamber out longer on 1895's so they can chamber their .457 WWG Mag it said you could also chamber the standard .410 shot.
From their FAQ page:
13. Can you shoot the 45/70 in your 457 Magnum guns?
Yes. You can also fire a 2½" .410 shotshell.
I thought about getting that done for a while, but decided I didn't really need it.