just playing devils advocate, but for an individual, casting all the lead at home and carrying it as round ball is lighter than carrying the same amount of un-cast lead "and" a ladle isn't it?
I think the idea is that you recover your lead and re cast it. Especially important for the big R.Bs that add up so quickly in weight. Also means you could carry/pack/float shot and cast ball out of it. Easier then cutting shot off a round ball!
Really just a matter of weighing a small single cavity R.B mold and ladle and seeing how much lead it displaces in your load. But your not carrying it around everywhere anyway. If it is in fact traveling with you 365 days a year your a fool for not having your woman or your dog pack it LOL.
Probably also gave you an edge when it came to bartering for lead. If you have no casting equipment and the other guy has R.B to fit your rifle/gun he is going to get alot more of your stuff out of the deal then if you trade for sprue cut offs and dirty spillage all mixed with ash and gravel.
Either way I'd love own any of those ladles pictured above.
