.450/.303 inch

In 1932 the Design Department took a commercial Kynoch .450 Nitro Express cartridge and necked it down to .303 inch to produce a plate test cartridge

.450/.303 inch Plate Test

As far as is known, this round had no official nomenclature but was in use for many years. It was designed to be fired from a pressure barrel (to design DD/E/1259) and from specially converted Pattern '14 rifles.

The case was a commercial .450 inch nitro case which retained its original headstamp of "KYNOCH 450 NITRO", but necked down to .303 inches. It had a Berdan primer and the cases were often reloaded.

The bullet was normally the standard .303 inch W Mark I armour-piercing bullet weighing 174 grains but other special bullets were loaded for test purposes. These included bullets of 100 grains and 70 and 80 grain aluminium bullets.

The charge weight depended on the purpose of the test as striking velocities could be adjusted to simulate different ranges.

The maximum muzzle velocity of the W Mark I bullet from the pressure barrel was 4,690 fps and for the 70 grain aluminium bullet 4,962 fps.

The .450/.303 inch round remained in service for plate testing for many years after WW2