This is an awesome place to live and hunt. You will take longer shots in Eastern Montana as it is lots of rolling hills and plains. In western Montana (where I live), rarely do I ever need to take a shot over 50 yards. I hunt almost exclusively with a muzzleloader and there are many non-game animals that can be hunted without a tag (squirrels, rabbits, porcupines etc) year round. You can buy deer, elk, and antelope over the counter, and you draw for sheep, moose and anterless deer & cow elk (depending on the area). 5 weeks of rifle season, archery starts the first sunday in September and ends in dec/jan. Grouse opens September 1 and we also have a spring/fall turkey. Occasinally there are drawings for buffalo. Link to Montana Fish, Wildlife and Parks http://fwp.mt.gov/default.html
I'll be happy to answer any other questions you have, if I can.