Well, the TCM is a round that relatively few casual shooters know exists. I have never seen a box of it in a store in my life either, something to consider. As these niche calibers tend to get their prices jacked up if a retail store ever did decide to carry it. I personally believe that it will run its course and disappear. With the highly anticipated .17 Winchester Super Magnum just around the corner id probably hold off and see if it lives up to the hype. To me its like the .45 GAP, they developed a round not too many people want/need.
