Lead shots for speaker stand.

Where can I buy this? No one seems to know what it is in any hardware stores
Snooker, any particular reason for the #7? I should be receiving a Lead Baloon turntable stand this week and plan on "loading" it with lead shot. I've been wondering what size though. Thanks.
Ditto on getting your lead shot from a hunting store -- better yet, a gun shop that carries reloading supplies. There are also several hunting equipment catalogs that sell lead shot. Lead shot is a bit harder to find than it used to be, since the federal hunting laws now require steel shot for hunting water fowl (birds were ingesting lead shot lying on the bottoms of ponds and getting poisoned).

Smaller shot usually works better for dampening -- easier to pour, more surface area, etc. I use either #7 or #9 shot in speaker stands, etc.
As an alternative to lead shot you might want to consider steel shot. Very inexpensive from industrial abrasives suppliers (~$20/50# bag). Available in sizes (grit) from course powder to ~ #6/7.

Much more enviromentally friendly if you dispose of it later and not a poison risk for children and pets.
As long as we're talking alternatives, and assuming you're looking to damp the ringing of metal stands and are not necessarily interested in making the stands heavier, try kitty litter. Real cheap experiment. Go to your local supermarket and pay $1.99 for a bag of Jonny Cat unscented kitty litter. Should be enough for one set of stands. Try it. If it doesn't do the job, you're out $2 plus sales tax.

If you are interested in adding weight to the stands, lead shot or sand would be better.
Try sand instead(you can get it in Home Depot for a few dollars). I try leadshot before and they sound very bad.