Reloading .303 British : Mk VII & Mk VIII (Z) ball ammo (long)

Source :

Army Ordnance Services Part 7 : Pamphlet No11

Small Arms Ammunition

Issued by the War Office - 24^th February 1945

(Extract from 131page document)

Mark 8Z 303-in SAA (Small Arms Ammunition) has a neoniteload and a streamlined based bullet. Trial firings have proved that these (Mk7and Mk8z) two types of ammunition do not wear the barrels in the same manner.Barrels which have been used for Mk7 or 303-in Tracer become inaccurate muchsooner when Mk8Z is used in them, than barrels in which Mk8z only has beenemployed.

One advantage of Mk8z ammunition is that the barrelmaintains accuracy and elevation until the actual moment of collapse. Noindication of approaching barrel failure is given when Mk8z ammunition is used.Accuracy is liable to break down very suddenly and the barrel becomes dangerousfor use for overhead fire in the latter stages of its life. To ensure thesafety of our own troops during overhead fire by medium machine guns, the lifeof a Vickers gun barrel using Mk8z SAA ONLY has, therefore been fixed at 10,000rounds (or 40 belts). This figure is well within the number of roundssuccessfully completed by the earliest failure of barrels firing and enduranceaccuracy test under conditions of excessively rapid rates of fire. If, howevereven a few rounds of cordite loaded SAA are fired, the Mk8z accuracy life dropsconsiderable.

The following instructions regarding the use of thesevarious types of 303-in SAA will be strictly enforced :-

a).303-in. Vickers machine gun battalions.

1)      Mk8zONLY to be used.

2)      Mixedbelts of Mk8z and tracer must NOT be used.

3)      Anybarrel that has fired Mk7 or .303-in tracer must NOT be used for firing Mk8Z

4)      Barrellife for Mk8Z is 10,000 rounds.

Barrels of Vickers machine guns in machine gun battalionswhich have fired Mk7, .303-in tracer. Or .303-in AP SAA will be stamped withthe figure 7 on the trunnion block and returned to ordnance through normalchannels. New barrels for use with Mk8z will be demanded in exchange.

b) Light Machine Guns*

Mk8z being neonite loaded gives a small flash at night. Whenthe Bren gun is being used for some special purpose at night, e.g. on a patrol,it may be desirable to make use of Mk8z in order to lessen the flash.

c) Rifles*

Mk8z SAA will not be used in rifles except as in the case ofthe Bren gun (see above), if necessity should arise.

*Although the use of Mk7 and kindred types of corditeloaded flat base, bulleted, ammunition reduces Mk8z barrel life, the reverse isnot the case. No deleterious effects will therefore be produced by theoccasional and restricted use of Mk8z ammunition in these weapons (Rifles) forthe purposes indicated above.