British, WWII - 1943 Dated, 20mm Oerlikon Mk II Anti-Aircraft Cannon Cartridge Case – M.P. / A.L. Broad Arrow Marked – Cut-Down Trench Art Variant

*British, WWII - 1943 Dated, 20mm Oerlikon Mk II Anti-Aircraft Cannon Cartridge Case – M.P. / A.L. Broad Arrow Marked – Cut-Down Trench Art Variant*

A genuine World War II British 20mm Oerlikon anti-aircraft cannon cartridge casing, dated 1943, retaining its wartime military markings and later shortened from its original service length. These powerful autocannon rounds armed Allied naval vessels, merchant ships, armoured vehicles and static anti-aircraft positions throughout the Second World War, becoming one of the most recognisable close-range defensive weapons of the conflict.

The base is clearly headstamped: M.P. 1943 A.L. ↑ 20-M.M.-MK.-2

The markings decode as:
20-M.M.-MK.-2 – British designation for the 20mm Mark II Oerlikon cartridge pattern.
1943 – Year of wartime manufacture.
M.P. – Manufacturer code for Manganese Bronze & Brass Co. Ltd., Ipswich, a wartime producer of ammunition components.
A.L. – Associated assembly or loading contractor mark.
Broad Arrow (↑) – British Government ownership and military acceptance mark.

The 20mm Oerlikon used the 20×110mm RB (rebated rim) cartridge, designed for the gun’s advanced blowback operating system. During WWII these guns became standard equipment aboard Royal Navy warships and merchant vessels, firing at approximately 450–500 rounds per minute against enemy aircraft and low-flying attack craft.

This example measures substantially shorter than a standard full-length service case, indicating it has been cut down by approximately 28mm after military use. Such modifications were extremely common after both World Wars, where spent cartridge cases were transformed into practical household or desk items.

Given its dimensions and style of shortening, this was likely repurposed as a: desk lighter sleeve; match or trinket holder; ashtray component or a decorative trench art item. The dark interior residue and shortened open mouth support the theory of post-service adaptation rather than a factory alteration.

Approx. Measurements – Height: 8.2 cm. Base diameter: 2.1 cm.

History Note:
The Oerlikon 20mm cannon was among the most successful Allied anti-aircraft weapons of WWII. Thousands equipped Royal Navy ships from corvettes and destroyers to larger capital vessels. Their compact design, reliability and devastating rate of fire made them particularly effective against low-flying aircraft and kamikaze attacks. Spent cases were often retained by servicemen and later adapted into keepsakes or practical objects, creating an enduring category of wartime trench art.

*Condition*
Cut-down example with service and age-related wear throughout. Surface patina and scattered oxidation spots present externally with heavy dark residue internally. Headstamp remains clearly legible. Please see photographs as part of the condition report.

JAQ#3202C_6167242126