Fullboar,
First off, for the best reloads, it is best to use one brand of brass, and MUCH better yet to have the brass be all of one lot number.
That is not likely to happen if your buying factory loaded ammo. Brand could be the same, but doubtful as to the lot #.
I have seen loads with the same brand of cases, Remington in this case, show extreme pressure while load develpment test were being done, all because of the difference in the brass from lot to lot.
If you have a digital scales, it would be reasonably quick to weigh your brass and in that way avoid any overly thick cases that could run up your pressures beyond the safe levels.
Best to buy your brass in bulk, as many as possible of one lot#.
Then, If your using a good cast boolit with a large meplat, close to 400gr or more and shooting a reasonable load as per velocity, you won't need any expansion for a quick killing shot.
Be aware, that some of the factory, jacketed 45/70 loads have the rep. of opening up waaaay to fast and too much, causing lots of damage to the critter.
Can't really speak to that other then what I read, as I have only used cast boolits for hunting and can see no reason to change.
Keep em Coming!
Crusty Deary Ol'Coot