".243 won't penetrate"?
I used a 6MM Rem. for years, wish I had it back!
I've recovered more .308 caliber bullets than I did .243/6MM, and I had plenty good blood trails too!
And as far as recoil goes, with the same type and weight of rifle theres not much difference in the recoil of the .308 and the '06! Different, but almost equal.
If a person is not going to huntanything bigger than deer a .243/6MM is plenty!