If so, go with heavier rounds, such as 77 gr loads instead of the lighter (55 gr, 62 gr, etc), common .223 rounds.

I have a 16" DMR rifle that will shoot sub MOA, I've qualified out to 600 yds on it, reliably hitting man-sized targets. The rifle is capable of better accuracy than I as a shooter am, and most quality rifles like BCM will do close to MOA.

The heavier rounds will certainly help at distance, the rest comes down to your ability to make wind calls and knowing bullet dope and other ballistic factors. You should be able to hit groundhog sized targets out to beyond 200 yds if you are a good shooter though. Trigger and scope are two other factors that will have a significant effect though, I shoot much better with the 2 stage trigger on my DMR than the single stage mil-spec trigger on my short range AR.