How can u tell from 200 yards?
You can't, it's a BS guess at best. People will talk about comparing the length to the ear, the face/snout, etc...which is still guess work. If you're extremely close to an elk it gets a little easier but I wouldn't be shooting on this rule 99% of the time. Antlers grow in funny ways sometimes and bulls have definitely existed that you could immediately look at them and know the brow was over 5", but those bulls also usually have enough other points not to worry about it.