Actually making them legal to hunt with in Colorado is very difficult. Making the 1000ft/lbs of energy at 100 yards is near impossible. (required to hunt in Colorado) I am not aware of any factory ammo that will make it legal to hunt with in Colorado .
Your own load listed above is NOT legal. Just over 1000ft/lbs at 50 yards, but shy of energy at 100 yards.
(page 12, top of the Colorado Hunting regs)
In fact I have looked at the Whisper, aka 300/221 aka ACC Blackout many times and it always falls short.
If you want an intermediate range AR the cheapest way to go to make it hunting legal is 7.62x39 or 6x45 (still hard to do in the 6x45 and 7.62x39). Next would be a 6.8SPC or 6.5 Grendel.