The Model 340 M&P is a J-frame Scandium/titanium alloy revolver chambered in .357 Magnum — the lightest factory .357 Magnum revolver available at approximately 12 oz. The extreme lightness makes .357 Magnum recoil formidable; most owners shoot .38 Special +P for practice and reserve the .357 Magnum loads for defensive carry. The AirLite designation indicates the Scandium frame. Type: Revolver Action: Double-Action Caliber: .357 Magnum Capacity: 5 Year introduced: 2004, USA Weight: 12 oz Overall length: 6.3" Status: Active Intended use: concealed_carry, self_defense, law_enforcement