Falling pressure regulator function?

[Hurricane Air Arms]

In high-end PCP's, I've noticed that, as the pressure drops, these airguns begin to dump more volume so to "cover" the drop-off.

IE

Instead of the shot pressures dramatically falling like so...
(Psi)
180
176
165
143
110
60

They fall more linearly until they weapon simply doesn't function
180
176
171
172
166
169
165

I may have to find the specific video, but the channel was AirGunTV and the air rifle was a Daystate of some sort.

SO the question is, how did they do it? Is there a spring-loaded pin that gradually increases in size as the pressure lowers, allowing more air to escape per shot?

I'm interested because I'm looking to build a semi-automatic, 5-shot PCP of my own and want to achieve a balanced deprecriation of my psi/volume ratio per shot.

As the pressure drops, I want the volume to increase to cover the losses.

Thanks

[jackssmirkingrevenge]

Many PCPs are to some extent "self regulating" around a certain pressure because as the pressure in the chamber goes down, there is less resistance keeping the valve shut, so with the same hammer strength, it opens quicker and longer as the pressure goes down.

The Daystates on the other hand are a little more sophisticated, instead of a spring-loaded hammer, they use a solenoid hammer to open the valve with circuitry that also measures the velocity, therefore it can calculate more or less how much it should increase the hammer force as the pressure starts to descend. Definitely not in the realm of a quick amateur project - you're better off using a regulated air supply, say for example a paintball bottle that is charged to 3000 psi but still gives a regular 450-850 psi depending on model and regulator until the bottle is almost empty.

[Hurricane Air Arms]

Of course! I mean, I figured as much, in my experience with home-built shrader valves that as the pressure dropped so did the resistance. I guess it comes down to the design of the pin/hammer valve for this to work. Granted the energy behind the striker is the same every pull of the trigger, then what you say should, in theory, work!

Also thanks for the super fast reply, Jack