US Cartridge, 3 inch Drill, M9, M10
This round consists of a 1 piece hollow bronze casting (cartridge case and projectile) simulating service ammunition. The nose is threaded to receive 21-second M42 Dummy Fuze. The round has a base that is threaded and screwed in rear of the drill cartridge; this base receives the inert dummy primer. Both the fuze and base are held in place by means of set screws.
The M9 Drill Round is used in all models of guns on fixed mounts, while the M10 is used on mobile mounts.