ANTIQUE Pre-owned Colt open top pocket model, 7-SHOT .22. Based on Colt's production records for the Open Top Pocket Model Revolver (.22 caliber), a firearm with serial number 77077 was manufactured in 1875. The Colt Open Top Pocket Model Revolver is a single-action, .22-caliber rimfire pocket revolver introduced by the Colt's Patent Fire Arms Manufacturing Company in 1871. Key Specifications & Design * Production Years: 1871-1877 * Total Built: Approximately 114,200 units * Caliber: .22 Short and .22 Long (black powder) * Capacity: 7-shot non-fluted cylinder * Action: Single-action * Barrel Lengths: 2 3/8 inches (60 mm) or 2 7/8 inches (73 mm) * Frame & Grips: Brass frame (often nickel- or silver-plated) paired with rosewood, walnut, or mother-of-pearl bird's-head grips.