I didn't get to add some advice in the other thread which was closed. I have a 6.8 SPC and have shot a couple deer with it. Mine is a 16" carbine. If you go this route I highly recomend the tactical loads having the extra 50 fps, they seem to hit harder and bring the cartridge up to speed. ALSO I am seriously considering doing another upper but with a 20" barrel this time to squeeze out the last drop of velocity. This round is really pretty impressive on the faster end of its range. And its really nice to have this in a standard AR size platform. FWIW mine dropped a pretty large buck this year.