The Mark I was Ruger's first firearm, a semi-automatic .22 LR pistol that launched the company in 1949. Bill Ruger designed it after studying the Japanese Nambu pistol, producing an American .22 target pistol at an accessible price. Type: Pistol Action: Semi-Automatic Caliber: .22 LR Capacity: 9 Year introduced: 1949, USA Weight: 36 oz Overall length: 8.75" Status: Discontinued Intended use: Target, Plinking, Training