I have a Model 70 ftw in .243WSSM
Shoots 70g and 75g bullets very well. The brass is the weak link though. Necks are very thick, limited supply, and factory ammo is scarce.
6br would be more accurate, and a regular .243 Win. more practical.
That being said I have no plans to get rid of mine. Shot several deer, and quite a few yotes with great results.
Some guys were running .243 WSSM single stack configuration AR platforms at one time.