Open Range, like most shows, are shots taken and modified heavily in post. With a mic capable of high SPL, a good pre, and some headphones, one can fairly quickly find the 'sweet' spot for recording weapons. But without sweetening, the weapon won't sound like Hollywood. In reality, most weapons on tape sound more like a 'crack' where in Hollywood they sound like a "boom"
An AT 4071 is a great mic for recording gunfire, starting at distances of about 10' and finding the best reflective area by moving around. Use the Pre to control volume going into DAT, Cam, whatever....
Then in post, use a create compressor with a fast attack and a slow release, adding just a touch of bottom, mid range dip, and a hair of high end, you'll have a nice boom. Try to keep it centered in the mix if dialog permits. That way you've got more mass covering a large sound.

Jan DBS was a typical shoot; pics at www.ar15.com by rickinvegas. I wasn't there; and the "professional" video apparently didn't happen.......but turnout is rising along with the temps!!