I like the last animation .
With the Grub screw restrictor to adjust the air port so then adjust closing time of valve .

Ok, this data was from a springer.
Found on internet .

Transfer ports .
Dunno if adds anything .
But here it is .

Huben K1 manufacturer's diagram:

Here's one I came across .

Something I acquired recently, a "classic" Coksai/Kokusai CAR-15 airsoft rifle:

20230318_092349[1].jpg

It works on the "bullet valve" principle that is relevant to the subject of this thread:

bulletvalve.gif

Some time in the future I'll do a detailed tear down to elucidate the operating ...

Hi

Maybe someone with more experience with the GGDT ,

Can explain why in the Dump ( 9999+ ms ) of valve .
In the results section : the pressure drop is not equal to the pressure in chamber .
( Train of thought if volume of chamber is completely dumped , it would equal the pressure
Drop ...

As above .
But in relation to point 2.

Ran scenarios through GGDT.
Regards to point 1.
.30 gram BB @ 5.95 mm
.603cm I'd barrel @ 43 cm long
Assuming 1.52cm3 dead space.
Asummed Nozzle , 5 mm I'd . Same as seat ?

Hi All ,

Not promoting anything so altered out names .

Product Description :

The ****** is a fixed volume system so only the air contained within the ******* cylinder is released down the barrel when fired. Therefore you use pressure to offset the need for more air volume to properly fill the ...

]" Having said all that .
For sake of simplicity and functioning .
Taking system of A pump Action , type cocking and trigger sear / using altering it , use a floating type bolt pull might be a simpler way to get feet wet , on build ."

Above , idea.

Watch this ,

https://youtu.be/VpvzIMOucKk ...

Above wrote ,
Make sense ,
Check out following pic .

https://sniperpedia.com/wp-content/uploads/2022/04/how-spring-airsoft-sniper-rifle-works-768x432.jpg

*Note: the spring actually goes into piston itself.
Is not drawn in .
Does not sit on back of piston.
As depicted and not seating in piston ...

Hey Dude ,

Not that straight forward .
Have to sit down and nutt out a plan , design .

They are mixed bag really .
Differ from makes and models .
Sizes may or may not line up with material able to get " off shelf".

Starting point and commonality amongst .
Comes down too , I.D. of cylinder ...

Finally found some time to think about this and I'm happier with this design:

https://i.imgur.com/lTrSFY0.jpg

Hi Jack ,

Popped up few times with balanced / timed valves .

If I may ,
Had play around few things on GGDT .
Seems 2MS , dwell , or close time .
Good number .

In the instance of ...

Boyle's Law. Not Susan Boyle.

For a given mass of confined gas at constant temperature, pressure multiplied by volume will be constant.

So for a starting state at pressure P₁ with chamber volume V₁, and a compressed state P₂ with final chamber volume V₂ :

P₁V₁ = P₂V₂

This gets combined with ...

Hi .

Purpose of question .
Work out the atmospheric pressure available within a cylinder , pre compression .

So then can work out , a compression ratio .
Gain desired or expected psi of the compressed air part / after the compression.

Atmospheric pressure is stated at 14.7 psi per inch squares ...

I definitely have a weakness for old and unusual airguns :)

I like the idea because it comes out of the conceptual "box" and is repeated all the time. There is always a different way to do the same with its pros and cons for sure.

I was unaware of this design when I posted almost the same ...