I am currently in the process of building a long range hunting rifle that I can pack but is still accurate to 700 yards maybe farther if my shooting gets better. I am starting with a Weatherby Mark V chambered in 340 wby mag. It is in an H-S precision stock. I am looking to put a new barrel on it with a break. Tune the action adjust the trigger and bed it. My gunsmith is recommending a Douglas or Hart if i want to go top of the line. I will be shooting 250 or 300 gr SMK handloads. Would you go 1:9 or 1:10 twist and what barrel, and brake manufacture. I am open to all sugestions but want to stay with the 340 wby.