Lead shot on its own is less successful that mixing it with a bit of sand, but the difference is subtle. Be careful to listen before and after as it is not a given that you will prefer the sound with your stands loaded. The sound can smooth out, the noise floor reduce and apparent bass extension improve. Equally the sound can become closed in and sluggish. How come? It depends on a variety of things, one of which is the floppiness or otherwise of your floor. For example a very floppy floor is best mated with light and rigid supports, whereas a rigid floor can work best with heavily damped supports.
