I enjoyed reading this thread. Always liked the hotrod rounds.
Surprised with the powder choices. I would think RL-33, Retumbo and maybe even US 869 might be better powders for this overbore chambering.
My 6mm-284 does very well with RL-33. Heavy 28" 5R bartlein 105 Berger hybrid 3535 fps.
Anyone ever try the slower powders?