I got some responses for powder selection for the 7RUM a week or so ago. I have a 338RUM also. Am I correct in assuming that slower powders would work better in the 7RUM than the 338RUM due to the smaller hole in a big case? I loaded up 102gr of Retumbo behind a moly 225gr AB in my 338RUM and was hearing some powder crunching when I seated the bullet (OAL to fit in the mag). This load is below max and avg velocity was 3006 fps from a 26" barrel. I would like to hit 3100 fps but don't like crunching powder. I bought some H1000 which is a little faster and looks to generate the same pressure with a few grains less powder. I'm thinking that the H1000 would work better in the 338RUM and the Retumbo would work better in the 7RUM--I'm going to use 150 gr bullets. What say you?