.455 inch Drill

Drill Mark I

The first dummy drill round to be introduced for the .455 inch revolver was "Cartridge S.A. Dummy Revolver .455 inch Mark I" which was approved to design RL 29465 and NOD 1565 in June 1920 and shown in LoC Paragraph 23951 dated June 1920.

In 1922 Lists of Changes stated that this cartridge was to be regarded as a drill round and the title was changed to "Cartridge S.A. Drill Revolver .455 inch Mark I" and in December 1927 it ws changed yet again to "Cartridge S.A. Dummy Revolver .455 inch D Mark I".

The .455 inch Drill Mark I had a white metal case with three short flutes in the side painted red (although some plain brass cases were used in WW2. The case was without cap, anvil or fire holes and the cap chamber was filled with a red fibre plug.

The bullet was similar in profile to the Mark II but weighed only 253 grains and was made of an alloy of 95% lead and 5% antimony. It was secured in the case by a neck cannelure and the mouth of the case was coned into the bullet.

Some early production of the Drill Mark I took place in 1920 before formal approval and the headstamp changed over time. Some included "N" to indicate Naval service and others had either the numeral "I" or "D I".

.455 inch Drill Mark I showing headstamp progression.