I'd take the .243 any day of the week! Inside 150 yards the deer would not know the difference between the .243 or the 30-30!
My luck, I'd get the buck of a lifetime that would be just out of the 30-30's range!
That same buck would be easy pickin's with the .243!
I do see the .243 as the minimum caliber, but it is a very good minimum!