I normally shoot 67 grain BT bullets, and have had considerable success with 13.5 twist Kreiger barrels. In South Africa at the WBC, I used a 13.75 Bartlien with the same pills and did OK.
I also have a 13.75-14 twist Bartlien that handles those bullets very well.
Yesterday I was running in a new 14 twist Maddco (Australian made) HV barrel with those bullets and this barrel has a 14 twist. Groups into the twos at 200 yards would seem to indicate no problems.