Throughout the service life of a gun, it would have visited the Armourers for refit, repair and general maintenance on many occasions. Generally, it would also visit the Armourer when transferring units or status. The tasks that an armourer would complete are included in the Instructions for Armourers.
Markings identified on Vickers machine guns include:
| D.P. | Drill Purpose |
| E.Y. | For Emergency Use only |
| 7 | Stamped on the trunnion blocks of barrels of Vickers machine guns in machine gun battalions that have fired .303-inch Mark VII, .303-inch tracer or .303-inch armour piercing small arms ammunition. It identifies them so they are not used with Mark VIIIz ammunition. |
Sources
- Goldsmith, 1994
- Skennerton, 1988; 1997
- The National Archives, WO 293/25 Army Council Instructions 1925.
