Loading speaker stands with?

Sand.  It's plenty dense enough, no need for lead.  Just make sure it's dried out first.

Lead shot is my preference.  Sand will absorb moisture over time and clump unless it's well dried first and sealed into the stand.

@cooperdude6 

I recently got some skylan stands for harbeth.  The owner said metal shot and sand were too heavy and would effect the sound.  Sand seems like a mess waiting to happen also.  He suggested wood pellets used for smokers.  I already had those so was simple.  He also said to not fill the legs completely, again to not add too much mass.  I don’t understand why nor did I try to but maybe check with your stand and speaker mfg. 

The Sound Anchor stands I recently posted about, were factory made for Harbeth 40 Series. Worked perfectly for the Omegas.

https://www.amazon.com/dp/B0CM4532P4? 

I have excellent experience with this steel shot to fill speaker stands. It's simply available on Amazon, will be delivered at your front door, and easily fills 2 decent size hollow stands with one bag. No futzing with the dust of sand or cat litter, and perfect size kernels. If you put a little cut of a plastic bag (or some other material/cloth) around the holes in your stand where you're leading your speaker cables through, nothing will fall out, yet the kernels are small enough to pour through smaller holes in the top of your stand using a simple kitchen funnel. It's heavy, non-toxic, and not dusty/messy. I've used it several times for many years on many stands and my stands are heavy, and "dead" sounding and no mess whatsoever. And it's pretty affordable and even reusable.