I assume you mean on his Encore. While some may have chambered a few Contender barrels for 22-250 at one time, most agree it is too much for the Contender, and no TC custom barrel shop I know of will chamber a Contender barrel for 22-250 now FWIW, not even for reduced loads.
+1 on what David said... a bag is good enough with the trigger guard of the TC right up against the bag. You can use your off hand under the grip to stabilize it and for elevation, just do not rest the grip on the bench or you'll most likely get verticle stringing.