Cooper Arms Model 21 Classic in 6mm Creedmoor. As the 6mm Creedmoor emerged from the precision rifle competition scene, Cooper was quick to chamber the Model 21 for it. The cartridge delivers 6.5 Creedmoor-class accuracy with a .243-diameter bullet at higher velocity, making it exceptional for both competition and varmint hunting. Cooper's hand-lapped barrels and tight chamber specifications maximize the round's inherent accuracy. Type: Rifle Action: Bolt-Action Caliber: 6mm Creedmoor Capacity: 1 Year introduced: 2017, USA Weight: 58 oz Overall length: 43.5" Status: Active Intended use: target shooting, varmint hunting, precision rifle