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Two other .303 inch Ball cartridges were introduced during WWI, both intended as training aids.
Mark VII Reduced Charge
"Cartridge S.A. Ball .303 inch Mark VIIz R.C." was approved to design IDW4507 in September 1918 for Air Service but was not shown in Lists of Changes.
The "R.C." in the title stands for "Reduced Charge" and the round was intended to simulate a Number I stoppage in the Vickers gun for training pilots in clearing jams in the air.
The case was as for the normal Mark VIIz but with a one inch blue band around the centre of the case. According to the specification the headstamp should include the letters "R C" but no such examples are known. It was also stated that the primer annulus should be black but this was later dropped.
The bullet was a normal 174 grain Mark VII.
The propellant was 31 grains of nitrocellulose.
Part of drawing IDW4507 showing proposed headstamp.
Mark VII Purple Label
"Cartridge S.A. Ball .303 inch Mark VIIz (Purple label)" was approved for Air Service but was not shown in Lists of Changes. The actual date of approval is not known and the title given here is presumed to be correct. The "Purple Label" is a reference to the colour of the packaging. Like the Mark VII R.C. described above, "Purple Label" ammunition was designed to give a No.2 stoppage in Vickers guns to assist in pilot training. This was achieved by seating the bullet lower in the case to give a round that was too short in overall length and thus misfed in the Vickers.
The case was the normal Mark VIIz case but the primer was blackened for identification. A normal ball headstamp was used. The example shown is "KN 1917 VII"
The bullet was a normal Mark VII seated 0.10 inches deeper into the case to reduce the cartridge overall length. Due to this there are no neck crimps in the case.
The propellant was 37 grains of Cordite MDT 5-2 to give a velocity of 2,440 fps.
Above: "Purple Label" round. Note lack of neck slit crimps to secure bullet. Right; headstamp showing blackened primer.
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