RE: Thompson Center
Let's see here, T/C is in Rochester NH right off of Rt16, Green Mountain is in Conway NH right off of Rt16. The distance between shops is less than 50 miles. I have done phone work for both companies. (Yeh I'm a telephone guy.)
I hope this isn't a big secret if it is I am sorry but GM has made tons of barrels for T/C. In fact after the fire GM made almost all of their barrels for a time.
Hope this helps.