The Grizzlies were playing just their second home game of the season. Montana (3-4) played five of its first six games on the road.
Montana pulled away steadily in the first half, taking a 35-21 lead at intermission.
Gregory got his first points of the game on a 3-pointer with 2:19 left - his only points in the first half. He scored 17 in the second half and finished the game shooting 8 of 12 from the field and 4 of 7 from distance. Breunig finished with 18 points on 8 of 13 shooting and grabbed seven rebounds. Brandon Gfeller added 10 points off the bench.
Lawrence Alexander led the Bison (4-4) with 29 points, hitting 11 of 20.