Uhhhh..... The 45-70 ammo.
Really.
Commercial ammo is loaded to the lowest common denominator. In this case, that would mean that 45-70 ammo at the store, has to be safe to fire in the weakest actions around, that the ammo might get stuffed into. For that particular caliber, you'd be working hard to find a gun that would be weaker than a Trapdoor Springfield.
It's loaded to levels equal to a not too lively black powder load, and unless the ammo says other wise on the box, should be safe in your new manufactured rifle.
IIRC there were a few loads out there that specified that they were not to be used in certain styles of firearms.
Your real worry is when you get handed someones reloads, that you don't know the exact provenance of. In a Ruger No.1, a 45-70 can be loaded up till it's as hot, or nearly, as a 458 Win Mag, and the Ruger will handle it OK. That same load will trash almost any other 45-70, though. Commercial loads are not that hot.
Cheers
Trev