The Oerlikon Cannon was a 20mm autocannon that saw extensive use throughout the Second World War by both sides as an anti-aircraft cannon. It had been designed by a German in World War One but under the terms of the Treaty of Versailles could not be manufactured in Germany. In 1924 the Swiss firm Oerlikon acquired the rights to manufacture the weapon. Initially supplies to the Royal Navy were imported from Switzerland, but the rights to license manufacture the gun were acquired and the first British made guns were delivered in March or April 1941. The weapon would serve as AA armament on many ships and as the primary weapon on some smaller craft. The weapon can be seen here on HMS Dido and relevant to today’s post is the distinctive magazine on the side of the gun:

Sadly it is unlikely I will ever have space (or the budget) for an Oerlikon, however the magazine is a bit more manageable and today we are looking at an example of one of these distinctive 60 round drum magazines. On the front face of the magazine is a handle to make it a little easier to carry and handle the heavy magazine:

The magazine is painted grey, with a distinctive zig-zag camouflage pattern around the drum and the words ‘Oerlikon’ stencilled above the feed lips:

The back of the magazine has an exposed axle to allow the magazine spring to be wound up with a crank handle when it is being filled, the spring being far too powerful to allow hand loading of the magazine unassisted:

The internal follower pushes the 60 cannon shells around an interior track until they come out at the mouth of the magazine, ready to be fed into the chamber of the cannon:

Not all cannon shells found their way to the enemy, as recalled by Jack Yeatman who served on the Trawler HMS Pearl:

The “Bristol squad” aboard the Asdic Trawler HMS “Pearl” formed a syndicate making very nice brass table-lamps. Ron Holbrook (HSD) had discovered that an Oerlikon shell was the same diameter as the fuze which screwed into the base of a 4” cordite case. “Gem” Class Asdic Trawlers had a 4” gun instead of the more usual 12-pounder, and whenever this gun was fired we went into operation.
Claridge (SD), young and strong, cut the base of the brass cordite case off with a hacksaw – no easy task. I then took it on watch with me and, during quiet times, rubbed away for hours on end with emery cloth and “Bluebell” till it was clean and shining.
Holbrook did the technical bits, brazing the screwed base of the fuze onto the bottom of an Oerlikon shell and, after screwing it into place, a brass lamp-holder onto the top. We used complete Oerlikon shells – the incendiary ones, because it was safer digging out the contents of these with a screwdriver than doing the same thing with the high-explosive ones. The result was a very attractive, heavy brass lamp, which we sold at £3 each – a lot of money in 1943. I still have two of them, one at my bedside now. (2005).
Our greatest problem was in getting the cordite cases. Unlike in John Wayne films, we didn’t spend our time in furious combat with the enemy. When E-boats did turn up, you weren’t likely even to see them, much less get a proper shot at one, and much the same applied to air attacks, which were usually by very fast, low-flying, fighter-bombers. So we had a waiting-list, and whenever we did let fly with the 4”, somebody would shout “That’s mine !”, and woe betide the gunner who let a case roll over the side.
We sometimes got 12-pounder cases from other trawlers and made table cigarette-lighters, with cut ·5 cartridge-cases brazed onto the rims, but it was the brass lamp production that really mattered and we made about 30 in all.
We also nearly killed ourselves – and everyone else !
The brazing job was done when we were tied up at No.8 Wharf in Plymouth, usually alongside two other trawlers. We worked in Ron’s Asdic Flat, a small compartment off the mess-deck, where charging batteries sizzled, and a big “No Smoking” notice hung on the door. We didn’t smoke – but we did use a Primus blow-lamp.

It was an old-pattern one, “straight up”, instead of the usual angled jet. One evening, it needed re-filling and re-lighting. Ron pumped it up, lit the meths pre-heater, but then turned on the paraffin too soon. A jet of flaming oil soared into the air, fell onto the deck and ran across it. (All “Pearl’s” decks were wooden, not steel.) Worse still, it trickled down around the edges of a large trap-door. This led to the spirit-locker directly below, containing the rum, and cans of petrol – and was next to the magazine ! The trap-door was, of course, padlocked, and the key was in the Wardroom.
I’ve never been so frightened in my life – none of us had. There was no point in running down to the Wardroom for the key – there wouldn’t be time if she was going to blow, and we’d all be on serious charges if she didn’t.

We poured sand down through the edges of the trap-door and literally held our breaths. Obviously nothing did happen, but it was a very long five minutes before we felt safe again. “Mysterious explosion in Plymouth – three trawlers lost” was the headline that DIDN’T appear. In the adjoining mess-deck the watch aboard was reading, playing dominoes, mending clothes, all blissfully unaware – and we certainly weren’t going to tell them.

I did, eventually – 45 years later at a Crew Reunion !