RE: Which is best? Thompson Center, or CVA
T/C makes a great rifle and the finish work is better on the T/C but, shooting wise, my optima mz shoots just as well as my buddies encore. He actually got a little PO'd about the whole thing for a little bit, seeing how he spent well over double on his rig. Now, only time will tell about durability and such but, for now, things are holding up well. I'm actually contemplating buying an Optima Elite in the near future.
T/C does offer magnum calibers for their frames. I didn't see any listing for the short magnums though.