I am doing my homework just now.
It seems that 1/9 30 cal barrels are none too common.
Anybody ever do a build with a 1/9 twist 30?
Yes I have a 300 RUM with a 1-9 twist I also have a new 1-8 twist 30 cal barrel that I am going to use. You should have no trouble finding a barrel maker that will supply a 9 twist 30 cal barrel.