All of the "factory" offerings are 12 twist which is just on the edge for stabilizing the 40 gr V-max. The 45 gr sp actually stabilizes better than the 40 v-max due to a shorter OAL.
Most factory tubes do quite well with the 39 gr sierra BK's.
What do you plan on using it for?
For yotes the 35 & 40 gr bergers and the hornady 45 gr SP are king. For varmints, my favorite is the 32 V-max and the 39 bk.
RL-10X, benchmark, H-4895 are my go to powders.
