20 x 102mm United States
Details
| Type | Inert, M55A2 |
|---|---|
| Projectile | steel, aluminum windscreen, black, 1 copper driving band Projectile Markings: (white ink) 20MM BALL M55A2 INERT KOP-SA-54-57 Driving Band Markings: ---KMO-3-41-58 20MM M55A2 |
| Case | brass, choke crimp Markings: (stamped) INERT |
| Primer | electric, flat, brass |
| Headstamp | [none] |
| Notes | Inert case filler. |