Jack Hatzenbuehler, 53, is facing charges of assault with a weapon and possession of a destructive device.
Officers told NBC Montana Hatzenbuehler was drinking for several hours at the Two Rivers Bar and Casino in Conner Friday night. He allegedly got into loud arguments with other men at the bar and threatened to return "locked and loaded." Witnesses said he came back later that night with a molotov cocktail and a lighter and told people he had a gun.
Witnesses told Darby Police Chief Larry Rose he would have lit off the explosive had several men not pinned him to the ground.
"This was serious. He was going to use it and throw it in there," said Rose.
The bartender who was working the night of the incident said that's not the first time she asked him to the leave the bar. On the 4th of July she had to remove him from the bar for similar behaviors.
Hatzenbuehler is out on bail. Bargoers say this kind of aggression is not normal in their community.