Cooper Arms Model 21 Montana Varminter in 22-250 Remington. The Montana Varminter stock configuration in 22-250 is Cooper's most practical long-range varmint tool — a broader forend for field use, 22-250 velocity for reaching distant prairie dogs, and Cooper's precision action for the accuracy to make that velocity count. A working man's high-end varmint rifle. Type: Rifle Action: Bolt-Action Caliber: 22-250 Remington Capacity: 1 Year introduced: 1993, USA Weight: 63 oz Overall length: 43" Status: Active Intended use: varmint hunting