First Pneumatic Speargun in France?

[popgun pete]

The pneumatic gun seems to start in France with this gun patented by Jean-Marie Ojard Chillet. It is a rudimentary gun with all the mechanical workings on the outside and is being patented during World War II when people are being fully preoccupied with many other things. I had thought that I would never see one until today when I saw the gun below which is shown as an unidentified underwater gun on the Frederic Dumas Museum website. If this gun really is the Ojard Chillet gun then this is a big find as it is the first patented underwater pneumatic speargun.. http://museedumas.fr/o/​

If this was a spring gun then the barrel would be full of ports which are there for anti-suction purposes when the gun shoots, but as you can see there are none. The proof will be in the presence of blow off ports in the muzzle as this is a dry barrel speargun which you tip the water out of after you cock it, then valves at the muzzle keep water out until the gun shoots when the air being compressed in the forward barrel tube by the rapidly moving piston coming forwards blows out through the muzzle valves. The spear is a close fit in the bore of the muzzle end cap and a coil spring sitting directly behind acts as the piston shock absorber. Very unusual and an idea cut from whole cloth as the old saying goes. The speargun is a forward latching gun as most of the early guns were.

 

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The piston in this skinny looking gun is about 0.5" diameter, although it could be even larger at 1.0" diameter as the inventor tried different barrel diameters and used whatever the gun could be loaded against in term of pressure at the cocked gun stage. The barrel inner diameter is virtually the same as the piston diameter with a leather seal fitted, this type of dynamic pressure seal being then used in vehicle suspensions and was also used in many subsequent pneumatic spearguns. The piston has a series of rings or annular grooves to cut down friction of the piston body running in the barrel tube and the gun barrel tube unscrews in the area near the trigger and just before the bend, the rear downward sloping tube section being the gun’s air reservoir. Because the gun is essentially a monotube the compression ratio is very high, maybe 4 or 5, so only a low start pressure will be able to be loaded against and yet will still give reasonable performance compared to the spring guns of the time (spring guns start in 1937, this gun starts in 1941). The inventor soon found that the piston pushing water along in a flooded forward barrel cut all the performance from the gun, so he decided to keep the forward barrel empty by tipping all the water out after first muzzle loading and thereby cocking the gun. This might sound a crazy idea today, but remember these early fish hunters were often swimming close to shore and could fire their spearguns at fish swimming around just below them without having to dive down, so these primitive by our modern standards guns would do the job expected of them at the time. Once spearfishermen gained more experience this type of gun was then taken to the next step of evolution with lower compression ratios and bigger air tanks, but everything has to start somewhere and this gun is that start and is probably the very first pneumatic underwater speargun on the planet. As such it should be better known and if you think of the guns used by the Nautilus crew in 20,000 leagues under sea this underwater rifle ticks all the boxes as the guns eject air bubbles as they shoot, but those shots are taken not very far underwater.

 

[popgun pete]

A must see, almost compulsory viewing, is this film by Jacques Cousteau. It is the earliest ever spearfishing film. I had heard of it previously, but until I found it today I had never seen it before. The spearfisherman being filmed is “Didi” or Frederic Dumas whom the museum is named after that I referred to as having an “Ojard Chillet” pneumatic speargun, probably the very first pneumatic gun anywhere. This film was an absolute sensation in its day and in my view it still is today.

Jacques-Yves Cousteau – “By 18 meters of Depth” (1942) or “Par 18 mètres de Fond”.

 

[popgun pete]

I was sent these photos of a home-made speargun that may be a pneumatic gun using the system shown above. The gun appears to be made of stainless steel tubing with stainless steel rod formed up and welded to create a skeleton mid-handle. A pull rod on the trigger runs forwards to operate a hinge type trigger at the muzzle, so the spear is held by friction created by the tilting metal tab until the hole through it aligns squarely to the shaft and lets it go. A monotube can act both as barrel and tank if the spear only travels part way down the tube to cock the gun, hence the missing spear will be shorter than the length of the gun. Quite a bit of work to make something like this, but a somewhat misplaced effort as this is not a great design by modern standards. Hard to know how old it is, but probably less than fifty years old. Probability of floating zero. Still interesting to see such an innovative piece of metalwork and welding.