Hello everyone. I have a .338LM GAP (30.5" tube) being delivered today and would like some help regarding load data, specifically powder selection. I know there's many threads out there with 338lm load info, but I think they're mostly shooting 27"-28" barrels. I'd like to know from some of you with experience loading for this, or similar, cartridges -- what's the best powder behind a 300smk to get the most efficiency out of this 30.5" bbl? I think I've narrowed it down to either RL25 or Retumbo. Any info would be GREATLY appreciated. Thank you, and happy holidays to you and yours.