SUPER RARE 1917 HOTCHKISS WW1 6 POUNDER GUN CASING

AWESOME ITEM. HOLDING HISTORY IN YOUR HAND. A VERY RARE BRASS SHELL CASING FROM WORLD WAR 1. ITS DATED 1917 SO ITS A 103 YEARS OLD CASING.
THE 6 POUNDER GUNS WAS MOUNTED ON THE MALE VERSION OF THE HOTCHKISS MARK I TO IV BRITISH TANKS. IT WAS HOWEVER PRIMARILY A NAVAL WEAPON MOUNTED ON SHIPS LIKE THE ARETHUSA, EARLY C CLASS CRUISERS AND SOME SUBMARINES.
The QF (Quick Firing) 6 pounder Hotchkiss was alight 2.25 inch (57 mm) naval gun and coast defence gun of the late 19thcentury used by many countries, and was also adapted for use in the early British tanks in World War I. 
The 6-pounder was used to equip Male versions of the early British Mk I - Mk III tanks. In 1916 the British Army was faced with the difficulty of quickly providing a new class of weapon. The existing Hotchkiss 6-pounder naval gun appeared to most closely meet the need(a compact enough weapon to fit into a tank sponson with a sufficient high explosive shell). A single gun was mounted in each sponson, i.e. two per Male tank able to fire forwards or to the side. Tanks armed only with machine guns were designated as 'Female'.
MARKINGS: a) 6 PR means Pounder which is shortened to"6-PR".  Pounder denotes a gun which fired a projectile of approximately 6 pounds.
b) III MEANS MARK III Mark 3 was the the same as the Hotchkiss Mark 1 but just longer.
Initially the Mk I and Mk II shortened single tube 6 pounders could only be fired with a lower charge but in 1917 they were relined with A tubes marked as Mk III which enabled them to use standard 6 pounder ammunition.
b) CF - Charge loaded with cordite England
c) 1917 Year of manufacture
d) K for Kynoch in Birmingham UK
e) Lot 75 Lot number for that year 1917
f) Ships Anchor Means it was propably used on a 6 pounder mounted on a naval ships during World War I like the Arethusa, early C class cruisers and a few submarines as well.
Size: The case is 57mm in diameter at the open end with a total length of 307mm.
There is a neck where the case diameter reduces around an 25mm below the open end.
Weight of casing: 1,1kg
Condition: A DENT ON THE FRONT RIM. SOME PATINA ON THE BRASS. PRIMER IS PIERCED.
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