Well, the valve was tested but it has a drawback that makes it almost useless.
I am referring to this piston valve design exclusively.
The practical problem is
that it does not retain the lubrication in the small 6.5 mm piston, and for this reason,
the o'ring breaks ... Perhaps the solution is to incorporate a lubrication system,
(I use silicone), but it complicates things a lot, and I am a lover of simple things.
My opinion is that the advantage of using a front seal on the firing barrel is that it does not need lubrication to
work properly.
The verdict is: It works well but it is not practical because of the problem I explained earlier.
The option of using lubricated air is not feasible because it fouls the igniter and the hybrid often does not fire.
Another issue is to include in the calculation of the relationship between the pistons, 6.5 mm - 16 mm,
in this case, the force necessary to open the valve, because this is a force that is added to that
of the larger piston, to seal the combustion chamber.
Here is a photo of the construction of
the 1045 steel valve. The larger piston includes the o'rings so that it is automatically depressurized
after each shot. All this works excellent, but the issue of the small o'ring breakage makes it unfeasible.