It seems odd that after so long writing this blog it is only now that we are looking at the standard MK VII .303 ball ammunition. This was the most common round of .303 in use by the British Empire for over fifty years and was used in Lee Enfield rifles and in Vickers, Bren and Lewis machine guns.
The MK VII round was first introduced in 1910 as a stop-gap until a new round was introduced (which did not in the end happen) and it was designed to take advantage of the new ‘spitzer’ shape of bullet introduced on the continent. The new round used the standard brass case of the existing .303 round and paired it with a long pointed bullet:The round retains the taper and prominent rim of earlier .303. The bullet itself was held into the case by three crimps on the neck:Happily I have an example of this round with a loose head so I can pull it out to show you:You can clearly see the cannelure where the crimps in the case engage. The hole in the base of the head hints at the lead and antimony core at the bottom of the bullet. Although a full metal jacketed round (and thus legal under The Hague Convention), the MK VII had a light-weight aluminium tip and a much denser lead base. Therefore although the round travelled through the air as normal, on contact with a human being the distribution of weight caused it to tumble making far more grievous wounds.
This diagram shows the internal components of a live MK VII round:The following excellent description is from the British Military Small Arms Ammo site and explains the round in far more detail than I could:
The new “Cartridge S.A. Ball .303 inch Mark VII” was approved to design RL17146 in November 1910 and shown in LoC Paragraph 15629 dated October 1911. The bullet was to design RL 17069B and both these designs were later replaced by DD/L/14006. Although use of the word “Cordite” in titles had lapsed in 1907, it was sometimes reintroduced to the Mark VII during World War I to distinguish it from the nitrocellulose loaded version. “Cartridge S.A. Ball .303 inch NC Mark VIIz” was approved in May 1916, loaded with DuPont No.16 powder.
The redesigned bullet weighed 174 grains and as introduced had a cannelure near the base into which the case neck was slit crimped. When neck coning replaced the slit crimps for bullet securement in 1944 the cannelure was moved to a new higher position. The bullet was flat based with an 8CRH ogive and a composite core, the forward part usually being aluminium and the rear part a 98/2% lead/antimony alloy. During wartime the aluminium tip was replaced by compressed paper, fibre or ceramic.
From 1911 until about 1943 the bullet envelope was cupro-nickel but from that date gilding metal clad steel became increasingly used. Post WW2 the envelope was generally gilding metal.
The propellant charge was about 37 grains of Cordite MDT 5-2 or 41 grains of nitrocellulose to give a muzzle velocity of 2,440 feet per second at a pressure of 19.5 tsi. A glazeboard or strawboard wad was placed above the propellant.
The headstamp included the numeral “VII” or “VIIZ (“7” or “7Z” after 1944) and a purple primer annulus was approved in June 1918.
The revised Mark VII served through two World Wars, the Korean War and countless other smaller confrontations. It was manufactured in all the major Commonwealth countries and vast quantities were manufactured in America on contract. This resulted in a number of variations, particularly in those manufactured in the United States where the bullets were made with all lead cores without the lighter tip filler. To maintain the weight at 174 grains, these bullets were slightly shorter than the normal Mark VII. Also, ammunition manufactured in the United States and some in Canada utilised a smaller Boxer cap than the normal Berdan one.
A huge variety of manufacturers produced .303 over the years, as witnessed by the head stamps:These two examples were made by Radway Green in 1942 and Royal Laboratory, Woolwich in 1932. For far more details about these rounds please look here.