20mm Dummy Training Round M55A3 Blue Tip Inert Aircraft Cannon Round Brass Case

Inert 20mm dummy/training round marked PBM-88D-556.011.M55A3 with blue projectile indicating non-live training use, complete with brass case and no primer or powder present; these types of rounds were commonly associated with mid to late Cold War aircraft cannon systems such as the M39 or M61 family, generally dating from roughly the 1960s through 1980s, and this example shows honest handling wear with good markings still visible, making it a solid display piece for aviation or ordnance collections while remaining completely safe and inert.