I was a member of the TCA for many years and let my membership run out last year. The contact is Hiliary or Joe Wright, in Mass. I have the address at home.
In my opinion, they have gone downhill in the last two years. They offer "special run barrels " every quarter, but they are priced as high as what you can have a custom shop make for you. There should be a link to them from the Thompson Center site.
I found membership was useful before the advent of these online forums , to learn more about TC products.
Greg