ALPHA C1 Pneumatic Speargun 14 mm inner barrel

You can see the pull rod here, the trigger has tiny upper claws that grab the spade like tab on the front end of the pull rod. Above the position where the pull rod enters the gun body is the automatic line release lever; you pull the trigger, the internal releasing valve slams rearwards and operates the line release lever before the shaft rockets out of the gun hauling the shooting line behind it. The releasing valve is the tap that opens the inner barrel up to full gun pressure and sends the piston forwards which in turn propels the spear.

No idea as I just put it together yesterday, but for sure it will have some power as we know from the videos. As for loading it, well I will be checking those aspects out before I go hunting with it as it is a bit bigger than my regular pneumatic gun. Here they are side by side as I was fitting the rear handle, the grip handle came detached in order to make for a smaller width package. It occurs to me that for air travel you could remove the handle for security and keep it with you as it attaches using only 3 cap screws, seen in these photos. The gun pumps up using its inner barrel, so you don't need to carry a separate hand pump.

A schematic showing how the power regulator works by closing the gap for the releasing valve to fly backwards into when firing at reduced power. The throttling effect of the reduced valve opening is used to slow the gas flow which limits the pressure build up rate in the inner barrel. Unlike the bulkhead partitioning system the Alpha C1 gun uses all the stored air from muzzle loading for the shot. Diagrams show guns shooting, top one maximum power, lower one reduced power.

Resetting the releasing valve for the next shot you push the rear butt forwards against its internal biasing coil spring. You cannot screw the rear butt right off as it travels between set limits. Dismantling the gun you can, but that involves undoing a few more parts. Although I have never done it some indicating marks could be added on the control knob surface to provide a set of different power positions which you could then in a sense dial up, say one or two alternatives as more than that and you will just confuse yourself.