Where can one purchase lead shot for speakers?

Lead shot is being replaced by other, safer heavy metals like Bismuth (non-toxic).

Lead shot was banned for waterfowl years ago so a number of non toxic materials are available including steel shot. Lead is still used for targets and upland game.

BB is a size of shot. 9 is usually as small as it gets with 8 and 7 1/7 more common for targets. Gets bigger depending on game with 6,5, and 4 for ducks, pheasants etc.
I doubt that shot size makes any difference for speaker stands.

If you want shot for speaker stands find a non toxic shot. It's probably best to keep lead out of your environment. It's no longer allowed in paint or gasoline because it's a toxic heavy metal.

Aloha Bill--I'm on Oahu. If you order have it shipped via Priority Mail Flat Rate. You can ship up to 70 lbs. for $13.95 if you can get it in the Flat Rate box, that is no problem with shot. My mailman has somebody here on the his route that has shot shipped. The box has 65 lbs of shot in it, all for $13.95. You can ship VIP Bricks the same way. Last month somebody here on Gon wanted $40 to ship a couple of VIP Bricks. You can probably ship 12 VIP Bricks in the Flat Rate box all for $13.95. Buy the way the Post Office does have smaller Flat Rate Boxs. A good way to ship cables with 3 or 4 days service.

Why don 't you use steel shot. It has a density of 7.85 g/cc . Lead has
a density of 11.35g/cc. Roughly a 30% increase in weight. with lead.
100% more safe with steel shot, no disposal problems, no health risks. You could also pack with pennies although they won't pack as well. Copper has a density if 8.96 c/cc. BTW.
Break out those jars of pennies.
Joe

Disposal problems? Health risks? Do any of you eat hormone laden meat, use armor all in your car, teflon covered pans or scotch guarded carpeting? All of which are as toxic as lead IMO- GOOGLE THEM!
I'd use the lead shot with a mask and keep it for your next project if you decide to sell the speakers. Lead shot is not just used for it's mass, but also for it's vibration characteristics and shape-non ringing as it tends to absorb vibrations, turning them into heat. Otherwise use sand or both. My $.02...