Mordem Saturno

This "Saturno" looks different inside to my recollection of the innards of the gun as it first appeared with the wand-like passive line release projecting forwards from the grip handle. The brass sear lever has an elongated slot for its pivot pin, so it pushes back for the relatch while it moves off the piece that the trigger moves when you shoot the gun. I cannot see that part, but if you take the trigger out then it may be possible to see it. So how it works is the sear tooth is first "up", held up by the blocking piece operated by the trigger, then the piston tail pushes on the tooth and drives it rearwards until it moves off whatever is underneath the front section of the sear at which moment the sear lever tips downwards and the mushroom tail catches on the tooth as the sear lever comes back up under the influence of its biasing spring. That biasing spring is a rubber ring! The piston under cocked gun pressure then drags the sear lever forwards until the mechanism is latched.

The sear lever mechanism is similar to the one in the much later Nemrod "Mariner", it too has an elongated slot in the sear lever. Only there a pull rod holds the front end of the sear lever up, the "Mariner" being a mid-handle pneumatic speargun. Other guns have used this design, the clue is the elongated slot in the sear lever that allows it to both pivot and move fore and aft to operate. Attached is a photo of the earlier gun in its pistol form.

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Jegwan said:

Makes completely sense Peter. My later model also has a pull rod below the front of the sear lever. Pulling the trigger makes the rod move forward - releasing the sear lever.

The piston was reversed in the gun - like shown on the picture - that's why I got confused.

The small SS hook is the one holding the spear and the anvil it goes through the shock absorber. Why didn't I think of that!

Many thanks,
Jégwan

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I thought that it was shown the wrong way around, so I rejigged your photo while trying to work it out. I wondered about the split tip at the now front end inserting into and holding the hollow(?) spear tail from the inside. If so a collet is missing to stop the piston blowing apart, something has to hold it together and also stop air leaking along the rod that forms the piston's spine.

Here is the parts diagram for the earlier version, same type of sear lever, so the gun operates in the same way. Mordem spearguns used to have rubber front sights and line wrap hooks that disintegrated over time leaving the muzzles bare. Note the holes in the rubber shock absorber sleeve! There is a bit more info here on the piston, now you can see all its parts. Note the spear tail termination that fits into the front face of the piston. The "Saturno" was up against the first version of the "Sten", a much simpler and more rugged gun which became the industry standard and probably still is, albeit with changes in style along the way. The "Saturno" has a ray-gun appearance which appears to be the intention when considering its name!

Yes, part 12 is the top of the mushroom head, part 11 is the mushroom stem. The piston is typical of the late sixties period where they were assemblies of a number of smaller sub-component parts. The coil spring allows the collar (part 7) to slide forwards and force the jaws closed on part 6 that are formed by the split in the front end of the rod so that they grip the spear tail extension which is usually a small metal ball on a tiny integral stem. When the gun shoots the piston slams into the anvil (part 16) which causes the collar (part 7) to slide back, the jaws to open and the spear tail to escape the grip of the piston. The collar and spring are trapped in place when those parts are screwed into the piston's centre section, part 9. The problem with these pistons is the jaws don't always work and the ball on the rear end of the shaft can be bent on its stalk, or worse still, break off when the owner keeps slamming the spear into the gun and it fails to be retained in the gun. Last guns that I know of using the ball-ended spears were the GSD pneumatic guns.

The Mordem "Strale" hydropneumatic was released in 1966, so the "Saturno" pneumatic will be some time after that. The low grip handle and the trigger operated slide running between side plates that moves the short pull rod are not the best design choices for a rear handle speargun, as we now know it can be done much easier and with fewer fiddly small parts that detract from reliability and take longer to assemble on the production line.

Looks like style has triumphed over substance if the gun is a sinker, which we now know that it is thanks to you. The "Saturno" would have found it difficult to compete with the "superlight" floating rear handle pneumatic guns arriving on the market just as it too appeared.