The Ross Rifle Co. Ross Rifle Mk III is a canada-made bolt-action rifle chambered in .303 British, introduced in 1910. Primary use: hunting, sport. Type: Rifle Action: Bolt-Action Caliber: .303 British Capacity: 5 Year introduced: 1910, Canada Weight: 112 oz Overall length: 44" Status: Discontinued Military use: Yes Intended use: hunting, sport