Not quite an elk:
25WSSM Dtech Rifle on a NY Deer
http://www.predatormastersforums.com...e#Post52661434


and another smaller on shot with a 25WSSM AR at 292 yards:
http://www.predatormastersforums.com...e#Post53015800


There are a lot of hunting forums where the AR platform is the preferred weapon... just not usually in 223/5.56. AR's in 5.56 are the preferred weapon for predators/varmints though.