There hasn't been any of the 120 SST's show up on the market in probably 2 years. Not sure if Hornandy has just been concentrating of the 100 grain CX or what. I have went to the 110 grain Vmax they are still available at a few vendors. Good luck with your search.
Are you looking for loaded ammo or bullets? I bought bullets from Midsouth a few months ago and it looks like Powdervalley and Grafs have the bullets in stock right now.