You may need to do a little more research:
From Bellmtcs.com
Thompson Center says you can freely swap handgun and rifle parts back and forth so long as you do not combine a buttstock and a barrel less than 16" or an overall length with a buttstock under the legal 26" limit.
The BATF...
I think the OP's original question had to do with a 1,000 yard TC.
You're recommendation is to cut up a perfectly good 7-08 and recommend a 308?
I guess some one needs to explain this to me...:rolleyes: