I have ran 223rem Carbine, mid, and Rifle length uppers, 6.8spc mid-length and 6.5 Grendel rifle length, and 204R rifle length uppers all on the same lowers, one an A2 rifle buffer set up and one a carbine buffer set up.
As long as you match up your buffer length and your tube length properly, then feed it enough gas, it'll run.