I grew up in Bozeman and return every fall to hunt with my dad and sister. It has always been hard to accurately guess distance, especially in the excitement. I used a .270 Winchester for 24 years with a fixed 6x scope. (Like @Alistair i just got used to basic estimations and it worked fine. A range finder helps us all be a lot more accurate, but also know when a shot is just too far. Nothing like antelope and elk hunting to get one confused on sizing in the scope picture. And the steep uphill or downhill shots can really mess with bullet drop. Even worse: buying new guns and then having to get used to a new caliber.