Lead shot was banned years ago for waterfowl hunting because it was being ingested by birds in the marshes. It's still allowed for upland hunting.
Because of the ban other non-toxic shot were introduced, the primary one being steel but there are others. If you want shot for your speaker stands seek out these other non-toxic materials. Any shotgun reloading supplier should have them. Because of weight and cost of shipping I would try to find a local source.
They come in different sizes, the higher the number the smaller (9, 8, 7 1/2, 6 etc.).
You should only use lead if you're into heavy metal 8^).