game4lunch,
The rut actually starts the same time each year. It is instict to start the rut. The weather, hunting pressure,length of daylight,and other factors will determine the activity level of the elk. It has to start the same time due to gestation period. If it is too early then the calves would not survive the late snow storms of the spring. If it is too late then the calves will not be big enough to survive the early snow. You are right on the money when you said the rut can go into October. Cows only stay in estrus for a short period of time. If they do not get bred then they come into cycle again in 14 days. So the rut will go as long as cows are coming into cycle. Elkcrazy is correct when he stated that early can be better. It all depends on when you like to hunt and what type of activity you like.
Good luck to all,
elkaholicid
Michael