B40FT B40 Military - 1965 B40GA WD B40 Australian Army MK 1 - 1967 B40GB WD B40 British Army MK 1 - 1967-70B40GN WD B40 British Navy MK 1 - 1969 B40GR WD B40 British Air Force MK 1 - 1968 - 70B40M B40 Military MK 2 - 1968-69 B40GD WD B40 Danish Army MK 1 - 1967-68 B40GD WD B40 Danish Army MK 1 - 1969-70 From 1969 onwards date prefixes were added. The first letter denotes the month: A January B February C March D April E May G June H July J August K September N October P November X December The second letter gives the year from August to July: C 1969 D 1970 E 1971 G 1972 H 1973 J 1974