The MP5 A3 is the collapsible-stock variant of the MP5, featuring a retractable two-position stock that reduces overall length for vehicle storage and concealed carry under a jacket. The 8.85-inch barrel and roller-delayed blowback mechanism are identical to the A2. The A3 is the most common MP5 variant in US law enforcement service — the collapsed stock configuration is practical for vehicle-mounted patrol and close-protection operations. Type: Rifle Action: Semi-Automatic Caliber: 9mm Capacity: 30 Year introduced: 1966, Germany Weight: 176 oz Overall length: 26.8" Status: Active Intended use: law_enforcement, collecting, historical