There's an airgun company with models out under the "AEA" name/brand,
and when checking them out, I spotted a very similar design used..
Here's a vid clip of one of them: It should start where the shroud is removed..
You'll be able to see the pressure activated spring loaded re-cocking mechanism
https://youtu.be/4hjl5gbdDfo?t=104
You initially cock the rifle, then fire it..
When fired, the extra air builds up inside of the shroud, at the front,
and the pressure than pushes back a front 'spring loaded plunger'..
As that action is blown rearward,
another component [rod/probe ] loads another round.. and repeat..
In effect, it's really close how the two work..
The downsides:
-The air version is said to be unable to add sound-suppression..
Apparently suppressing altered the air pressure at the front end,
and negatively effected the movement of the re-cocking mechanism..
- The air version is said to be speed-limited since after the first shot,
and follow-up-shots, it takes X amount of time for the re-cocking mech to do it's thing..
So, it's still semi-auto, just not super-fast rapid-fire semi-auto.
[as fast as you can pull the trigger won't work] Still a cool concept though!
Sam -
