Id do a plain old 6-06, 7.5 twist on a 1 or 2 contour. Inexpensive brass, ability to shoot about any bullet you want and no real detractors I can think of in the Kimber.
What he said. Although I would definitely do a number 2 contour, they get that muzzle up to .60” to balance a bit muzzle heavy.
More capacity than a 240, great brass, ability to throat as per your wishes, pointy 6mm bullets, enough mag length in the Kimber. No down side.
