Re: barrel twist
I don't have a 338 RUM but I do have a
338-06 Ai , it has a 1-12 twist and shoots the 200gr Nosler Ballistic tips and 210gr Nosler Partitions great.
My velocity is just over 2500fps out of a 22" barrel , I would think that the faster 338Rum would use maybe a 1-13 but why risk it ? Your not gonna realy gain any velocity by going to that much slower twist.