I make what I've called "birdslugs".
I have a Saiga 12s with drum magazines that gets expensive to feed. And my club doesn't allow shot on the rifle/pistol line where you plink. They allow #8 shot on steel in the action bays though. So I needed a supply of "plinking slugs".
So without a supply of shotgun loading components, (now I have tons) I took to buying the Wallyworld 100 round Federal bulk packs, prying open the crimp, dumping the shot and recasting it as 1oz Foster slugs using a Lee mold, and re-loading/re-crimping them using a Lee Load-All II.
The Lee 1oz Foster slug mold is .69 caliber so it fits in a standard shot cup inside the shell so you don't need any unusual wads.
And since the shells are 1-1/8oz of shot, a 1oz slug doesn't create any pressure issues. And a slug doesn't obdurate the bore/squeeze sideways on firing as much as shot does. Not the most accurate things out there, I wouldn't hunt with them, but for high capacity blasting/plinking ammo, or at house/room distances they'll do the job.