Milbro “Cub” Automatic Air Pistol (1946 to 1980s)

The Milbro Cub “automatic” air pistol is actually a French design that was manufactured by Pneuma-Tir as the “PNEUMA-TIR 500” from the mid 1940s, perhaps 1946, to sometime in the 1980s. That’s quite an impressive production run! Mind you, I’m not so sure that the British Milbro Cub was produced for as long as the French PNEUMA-TIR 500.

With the breech plug removed you can just see the entrance to the magazine tube that runs inside the grip.

The pistol design is quite unique. It has no trigger, piston or mainspring. In fact his has no moving parts at all! Instead, the incredibly tiny 2mm lead BBs are propelled out through the barrel by squeezing a rubber bulb that is contained in the grip. Typically, these rubber bulbs that are similar to those of your doctor’s blood pressure instruments have perished and are usually found in an unusable solid condition. At the back of the pistol is a black threaded plug. When removed, up to 500 of the 2mm lead BBs can be loaded into a cavity in the grip behind the bulb.

To prepare the pistol for shooting, the muzzle is tilted downwards causing a BB to roll into the breech. A latex diaphragm or valve with a small central hole prevents the BB from rolling straight out of the barrel. A gentle squeeze of the bulb would indicate that a BB is loaded. This is due to a sense of pressure building up in the bulb as the BB forms a seal on the hole of the diaphragm. A sharp squeeze would build up enough pressure to force the BB through the rubber diaphragm and on its way to its target.

It is clear that whilst the pistol was advertised as “automatic”, it wasn’t really. However, it would probably be fairly quick to fire each shot in succession up to 500 times! Kids back then must have developed giant forearms and hands!

On the right hand side behind the pseudo slide grip and just ahead of the rear plastic magazine plug was stamped  “VALVE” with “→1” and “→2” that indicated that the pistol had two valves. The valves are actually the latex diaphragms described in the patent. Removal of one of the valves would require less pressure to force the BB through the hole in the diaphragm and therefore would reduce the power of the pistol. Somehow I doubt anyone used the pistol with less than the full quota of valves.

The rear sight would be aligned to one of the valve indicators.

The “→1” and “→2” marks were actually provided for use with the rear sight. The owner would align the sight with whichever mark coincided with the number of valves fitted to the pistol. Sadly, this pistol is missing the rear sight. However, a diagram of it is shown in the instruction manual.

On both sides of the pistol above the grip is stamped “MILBRO CUB”, “CALIBRE 2M/M 55”. The 55 is somewhat puzzling. However, I have a theory. Some say it is “.55”. That cannot be an imperial equivalent of the pistol’s 2 mm calibre. To explain my theory we need to take a close look at the British patent.

The British patent application consisted of two French patents.

Originally, the invention related to this air pistol was filed in France. In fact two patents were filed, one on November 22nd 1945 and the other on May 23rd 1946. Both of these patents were later filed as one combined patent in Great Britain on July 23rd 1946 as application numbers 21954/46 and 21955/46. Hence on the base of the grip of the pistol you will note the stamp “BRITISH PATENT APP No 21954-5-46”. Amongst other designs or applications of the invention is clearly shown a diagram of the pistol and its construction. My theory is that application 21955-46 relates to the pistol and hence the “55” stamped onto its side. That’s quite a hunch and without finding the original individual French patents I am unable to prove my theory. Alternatively it could just be a marketing gimmick.

The actual British Patent number, not the application number, is 614,740 and is titled “Improvements in or relating to Pneumatic Devices for Throwing Small Projectiles”. The patent is focused mainly on the rubber diaphragms and how they are used to provide the means for “throwing small projectiles”. That’s right, something as simple as a flexible rubber disc with a hole in the middle is an invention which can be patented! Yet the patent document is a whopping 17 pages long! Surely that can’t be right. Although the invention is for that small rubber disc, the patent goes to great length to describe how it is used and more interestingly for us, detailed drawings of various applications that it could be used within.

The inventor, René Boulet, certainly had quite an imagination. Included in his patent are drawings for a cigarette holder, a covert projectile thrower that would be concealed within a mouth, a smoking pipe, a pistol and a rifle. All of these included the principle invention of the projectile thrower and you have to wonder whether the concealed nature of the cigarette holder and smoking pipe had some clandestine purpose. However, a design intended for such a purpose would be unlikely to be made public via a patent. It is much more likely that these designs were intended as toys. Especially when you realise that these designs were incredibly low powered!

This particular example is finished as bright polished alloy and was supplied with a box of BBs, a cleaning rod, spare diaphragms, an adjustable rear sight which would be pushed into the magazine plug and an instruction manual. It may have originally been supplied with a metal spinning target. The pistol was also available in black and I have read that purple anodised models may also have been sold. Later French PNEUMA-TIR models were also produced in various transparent coloured plastic and supplied in cardboard boxes with polystyrene inserts along with a tube of BBs.

Certainly, the PNEUMA-TIR 500 could be purchased as a carbine model. The basic pistol was exactly the same however it was supplied in a longer cardboard box along with a wire shoulder stock and longer barrel. An absolutely stunning example sold at Rock Island Auction on December 5th 2014 for $1,495 plus auction fees! Later PNEUMA-TIR carbine models were sold in cardboard boxes with polystyrene inserts and a plastic shoulder stock with extended removable barrels. The barrels simply screwed into the muzzle replacing the plastic muzzle and barrel locating cap. The carbine barrel and shoulder stock was also available as an optional purchase.

PNEUMA-TIR 500 “Carbine” courtesy of Rock Island Auctions

Ammunition was supplied in small envelopes of 500 BBs that were ready to be poured into the pistol’s magazine cavity. Boxes of 2000 were also available from Milbro as well as packets of spare diaphragms. No. 7 birdshot may have also been used as a substitute for the 2mm BBs.

The Milbro Cub is fairly rare to find in the UK and most if not all are in a non-working condition. I have only ever seen boxed examples which were probably stored away in grandma’s sock draw or a loft and forgotten about for decades. Those without a box are unlikely to have escaped the fate of the rubbish bin. There are a number of the later French plastic PNEUMA-TIR pistols available in France. Some are complete with their boxes and are in very good condition. However, the vintage PNEUMA-TIR 500 and Milbro Cub are of most interest to collectors.

Until next time, happy shooting!

Jimmie Dee

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