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Easy loading pneumatic gun using power switch

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Well-Known Member
Aug 13, 2007
I had not actually ever used this way of easy loading the gun so I thought it would be interesting to say few words about it. I mainly used power regulator lower power switch just to diminish outgoing speed of the spear. But that switch also has easy loading purpose. You can not see it working if you load the shaft in one continuous motion. In that case the loading would be actually more difficult. You'll need some additional power against the valves spring resistance ( it is about 2 kgf). But you can load the shaft in pumping motions, down-up, down-up, until you latch the piston. It is similar to the action of the hammer. Instead of pushing on the nail head with the hammer to get the nail in a wood you hit the nail with a hammer.


Jul 1, 2022
I have had some old pneumatic airguns, I'm not sure if they work the same as "modern" ones.
However one airgun had a power regulator and could be loaded with less initial force using the method you describe.
With this gun the low power setting stopped the bidirectional free movement of air between the two air chamber. However due to a one way valve, each time you push the shaft a few inches forward you are moving the air from chamber 1 to chamber 2.
The air will not return to the chamber 1. Therefore if you move the shaft back out of the barrel, the pressure at the starting point of the loading phase will be lower than the previous time you started to load it. The initial force required to push the shaft back inwards again is therefore less*, this combined with perhaps some momentum (I like your analogy of the hammer and nail!) made it seem like less overall force was needed.

*Until you compress the air in chamber 1 to the same pressure as chamber 2.

I don't know if airguns manufactured today still use the same basic designs?

I have ordered a salvimar pneumatic - it does have a regulator but I don't think I will need as it is only 85cm and I'm not planning on using a pressure over 20bar.

I would however be interested in using scales to see the forces required loading with different techniques and power settings - however I'm not sure how to keep it lubricated/wet whilst loading out of water.
popgun pete

popgun pete

Well-Known Member
Jul 30, 2008
All pneumatic spearguns with a partitioned air reservoir use this power regulator system. The power switch or lever controls a downstream valve in the partitioning bulkhead. Salvimar guns use an upstream valve, so the power positions are reversed in the power selector gate, which means full power is forwards and down in the gate, not back. In these guns the non-return valve in the bulkhead and the power regulator valve are the same item (see below).
Mares 1979 schematic 800x562

Predathor diag

Any tests on land to check the loading effort hose the gun to drench it with water first or dunk it end for end in a bucket of water. Utmost caution is required as if you cock the gun then so do so against a block of wood with the gun pointing downwards and the spear tip trapped. Pull the trigger with all your weight pressed against the handle and allow the shaft to very slowly exit the gun in a controlled motion. Anything else and there can be big trouble.
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