My No.1 in 375 H&H wouldn't shoot worth beans with RL-15 or IMR 4064 using Speer GS 285gr, Sierra 300gr SPBT, or Nosler 300gr Partition's. I'm talking 4-5" groups at 100. When I tried IMR4350 and H4350 under the same three bullets it became accurate like JGray's rifle. It was such an abrupt turn around that I thought it was obviously my operator error with the previous test results using RL-15 and IMR 4064. So I tried again with the medium burners and got the exact same big groups. Never saw such a huge difference in any of my rifles with just a powder switch. I mainly shoot LBT LFN 250gr. cast bullets (sized .379") with 43.0gr IMR 3031 @ 2000 fps for practice and fun. It's very accurate with cast bullets.
