A 2 year old bull is a raghorn in my book. Most typically a small 3,4, or 5 point, I've seen a few 5x6 and 6x6, and one 6x7 raghorn. So I'll disagree with JDB to the extent I don't consider a mature bull with inferior antler development a raghorn. It is about age, not points.
I'm sure there are regional differences, based on typical antler growth for the area. In herds where yearling bulls commonly grow branched antlers, I consider those 2-pt yearlings or 3-pt yearlings - not raghorns.