An article in the new Hodgdon Annual makes a good point about the advantage the .243 has over the 6CM as a dual-purpose round, based on the usual throating of .243s. The test results bore that notion out, with only one "varmint" load for the CM doing really well.
My .243 is an oddball, with a 7.7" twist and a long throat, which has varmint-weight bullets hanging onto the case neck with their toenails.
