Hand written Range Table for Mk VIIIz .303 ammunition : 2/2 Australian Machine Gun Battalion

Range table, hand written in black ink on lambskin, for Mk VIIIz .303 ammunition. The table is actually made up of two separate charts, each graduated down the left hand side in 50 foot intervals up to 4500 (the maximum range of Mk VIIIz ball ammunition). The left hand chart then has columns for 'T.A.', S.A.', E.q.R.', 'C.C.L.' (angle), 'Minimum Clearance', 'Time', 'Dimen's B.Z.' and 'Slope (1 in)'. The left hand table has columns for 'Lift 50*', 'Lif 3&9', '2-4-8-10', '1-5-7-11', '6-12', 'Tem 60' (degrees) and 'Bar 30"'.

When Mk VIIIz ammunition was first issued to machine gun units in the Middle East in 1942, no range tables or slide rules were issued to accompany it. 2/2 Australian Machine Gun Battalion, faced with this problem, set out to devise its own tables, and two Sergeants of A Company, John Cockram and Gus Longhurst, undertook the task. Eventually their calculations were completed and, in the absence of suitable heavy-duty paper, were copied onto a lambskin which Cockram had acquired in Beirut to have made into a gift. The new tables proved entirely successful, and were later used by the battalion during the fighting at El Alamein, enabling accurate indirect fire to be delivered at ranges of over 3600 yards. Mk VIII .303 ball ammunition was a streamlined and boat-tailed development allowing greater range through improved ballistic design. Mk VIII was propelled by cordite, but the more powerful MkVIIIz, propelled by nitro-cellulose, increased useful range to 4500 yards, and muzzle velocity to 2500 feet per second. The creation of the tables is described on page 86 of 2/2 Australian Machine Gun Battalion's history, 'Muzzle Blast', which also features a photograph of the V I Graph.

• Hand written Vertical Interval graph for Mk VIIIz .303 ammunition : 2/2 Australian Machine Gun Battalion