An AR is going to be a pretty big handicap in a lot of ways. Wind, of course, is an issue, but a larger concern is that small, slow bullet makes spotting hits a lot harder on steel. The steel is usually so shot up that the only way the RO can call hits is sound, and if the plate move. Many times, a .223 just wont swing the plate. Not saying it can't be done, and definitely cant say it won't be fun....but it will be tough.
This may or may not be an issue. Top competitors are migrating toward 6mm from 6.5 to help reduce recoil since a lot of matches have sensors to detect hits. You don't necessarily have to "spot" them anymore.
