Brisk business at Great Falls gun store MTN NEWS and last updated 2021-01-19 16:47:27-05 GREAT FALLS â Business is booming at gun stores, including at Mitchell Supply in Great Falls. Owner James Mitchell and his wife said Tuesday that business had been hectic the past two weeks, especially last week. He says there have been a lot of first time buyers, and the most popular items are AR-15 rifles and handguns. Ammo is also in high demand ( "With the election going the way it did, yes, we knew people would be concerned. Especially since they keep talking about limiting gun rights,â Mitchell said. "They want to get it while it's still legal and while they can purchase it.â