45/70 loads just like any other straight walled handgun or rifle round. Since it's so long and big around, it needs to be well lubed. Since it's so long and has limited taper, it doesn't grow in length too much.
Here's one of my loads/boolits;
These were dipped in lee liquid alox, then allowed to drain. They were then sized to .459.
Then loaded in starline nickel plated cases.
That's a lee special order group buy from over on the cast boolits forum. It weighs in at 420 grains and is downright accurate. I shoot these in my NEF buffalo classic.
Oh, there has never been a 45 acp with a bullet at .454. Some early colt SA revolver 45 colts were .454 diameter, now they're all ,452, just like the 45 acp.