Just a year ago (almost) Thompson Center introduced the Dimension interchangeable barrel bolt action rifle system and here we are on the edge of 2013 and I finally am receiving my first shipment of Dimension magazines. 
   Initially I have ordered 2 of each magazine family. This is probably a great time to refresh the Dimension family tree:

"A" Family Magazine-TC9848- for the 204 Ruger, and the 223 Remington
"B" Family Magazine-TC9838- for the 243 Win, 7mm-08 Rem and the 308 Win
"B" Family Magazine-TC9846- for the 22-250 Remington
"C" Family Magazine-TC9828- for the 270 Win and 30-06 Springfield
"D" Family Magazine-TC9832- for the 7mm Rem Mag and the 300 Win Mag

Notice the fact that there are 2 "B" Family Magazines for obvious reasons the differences in case size has required this.
   Here is another thing I have found, either all my suppliers are confused or those TC magazine numbers cross reference with the Venture magazines? I need to investigate this more thoroughly before I announce this to be fact.
   You will see these magazines available on my site at hausofarms.com and also on my Ebay listings.
   Shoot straight and be safe. Marty