I've never owned a 6XC, so I can't comment there....
The 243 is my favorite cartridge. Factory 700's and 77's will easily kiss a 105 before you reach mag box limits. They'll spin 'em too. The Ruger American Rifle will also do the same with its detachable box and is a fun, affordable toy.
Throw a SWFA 6x on top of a 243 RAR and buy some 105's. The results will be more impressive than the $700 you have invested in the platform.
