
            | Type | Dummy, MK 100 | 
|---|---|
| Projectile | steel, aluminum windscreen, gold, 1 copper driving band Projectile Markings: (black ink) 20MM DUMMY INERT FOR GUN MK12 (stamped on fuze) 1211649-A-1 Driving Band Markings: *20-MM MK.11-0 A LOT MMC 1-15* | 
| Case | steel, choke crimp, cadmium plated, 6 holes Markings: (black ink) RNO 1-285 | 
| Primer | none | 
| Headstamp | 20MM-MK5. MOD.0 RNO . 8 . 65 . |