I've hunted them in November in southwest Montana, and most of the big bucks were dropping their horns the first week of November. I shot my buck on the 2nd or 3rd, as he still had both horns and when I went to lift his head up to look at it, the horns both slipped right off. We noticed that the smaller bucks all still had their horns, but we were onto some really nice bucks, and several of them had dropped that very day. It sucks to finally get on a 15+ inch buck you've been hunting for days, only to realize that he has 1 horn that day!