You can do as a friend of mine used to. He didn't want to bother casting slugs (or bullets in general). but wanted to hunt deer with BP slug loads in his SxS damascus.
So he simply bought a couple 5-packs of over the counter on sale Foster type slugs. Whatever was cheapest, and cut the shells open to get the slugs themselves out. Then loaded the lead into his own BP shells. Like he used to say, how many rounds do I need anyway,,10 ought to do it for the season.
I usually did and then some.
Saved a lot of time, effort and expense as he saw it.
(I think He used to reload the slug shells w/a light load of shot and use them up too but he never told anybody)
