Thought I'd throw my .02 cents worth in even if a bit late... I have both contenders and encores, in both pistol and rifle configurations which is of course the beauty of the Thompson set up.
I agree with the idea of the 308 based case thru a 15" encore. I think you'll get all the performance you need with a little better recoil characteristics.
I think the Thompsons deliver recoil very well, and are very comfortable to shoot but as they say your mileage may vary.
I don't believe mine is at all unpleasant in 7mm-08 and would liken it to my 44 Mag Super Red Hawk with stout loads.
I just received a replacement 7mm-08 barrel from Thompson as my first had a problem with the crown. I haven't even fired it yet as I have too many other barrels.
I would be comfortable shooting out to about 150 yards but feel the gun is quite capable of shots considerably further. I won't take a shot I'm not comfortable with and consider 150 yards to be my effective limit not the gun's. With a 7MM-08 I think this gun is quite capable of 300 to 350 yard shots if not further.
You might want to talk to some dedicated shooters and builders. Give Fred Smith a call at Bullberry and he'll help you figure out what you need.
Another great contact is Ed's Contenders outa OK. Ed can help you get hooked up with Frames, Barrels and just about anything else you might need to get started and the prices are a lot better than you'll find elsewhere.
Also take a look at Mike Bellm's forum and you'll run into guys who regularly and consistently shoot these guns and can talk more accurately about what they're capable of.
Then when it's all said and done, buy a 7mm-08 and if you aren't happy sell it and try another... <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
