To identify the various types of cartridges employed with the equipment when carried in the trailer ammuntion boxes, the safety clips are painted as follows :-
Full charge rounds
H.E. Clip uncoloured.
Shrapnel. Clip painted red.
Smoke. Clip painted green.
A.P. Clip painted blue.
Reduced charges
H.E. Long arm painted white.
Streamline shell
H.E. Long arm painted yellow.
Smoke. Green with long arm painted yellow.
Blank. Long arm painted black
Source: Handbook O.Q.F. 18-PR Marks IV, IVA and IVB. 1940
Clip, Cartridge, Q.F. 18-PR., Mark I
The clip is made of brass, cross shaped so as to form four arms, the ends of which are turned in to form clips to engage with the rim of the cartridge case. One arm is painted red, and is slightly longer than the others, the clip portion being differently shaped, so as to spring over the rim of the cartridge. The other three arms are sand blasted and black lacquered. It has a canvas loop for withdrawing the cartridge from the baskets or tubes in the ammunition boxes of the limbers and wagons.
Source: Handbook of the 18-PR. Q.F. Gun. 1915.