re: AR hunting rifle?

To me the biggest advantage of the .300 blk is having one rifle that will handle two calibers with just the change of the upper. Pop two pins and bingo a different weapon platform. Already having several AR-15 rifles and many mags for them makes the .300blk a no brainer in my case as compared to the 6.8 or even a .308, 7mm-08 etc. in the AR platform.