Regulator plenum size bigger or smaller?

[stevensuf]

I have a Hatsan Vectis that I would like to regulate, i did order a lane regulator for it, but they sent the wrong diameter.

Now It has me thinking, i would like to achieve around 18fpe, the gun has been opened  so all port are 4.5mm and it breathes
well now. My question is, if i use a smaller plenum i take up less tank space, but would probably need to work at a higher pressure
to get the power i want, if i use a larger plenum then i could probably get the power i want at a lower pressure, but loose more tank
space..

So as to shot count, which would be better, a smaller plenum at a higher pressure loosing less tank space or a bigger plenum
at lower pressure , loosing more tank space but i can operate the tank down to a lower pressure?

Any ideas?

cheers
Steven

[CableStop]

What caliber Vectis do you have?  Generally I'd suggest the largest plenum you can reasonably fit into the rifle, that way you get the lowest pressure drop through the shot cycle.  This allows you to use less valve dwell, and a shorter cycle of the valve will usually be more efficient. 

[HunterWhite]

Have you read these?

https://www.gatewaytoairguns.org/GTA/index.php?topic=97924.0

https://www.gatewaytoairguns.org/GTA/index.php?topic=128343.0


https://www.gatewaytoairguns.org/GTA/index.php?topic=161814.0


https://www.gatewaytoairguns.org/GTA/index.php?topic=148850.0



H T H

Hunter

[Cableaddict]

Someone on these forums recently told me that you want as many cc's as you maximum fpe you intend to shoot.   Past that is just a waste, regarless of porting and valve mods.

I don't know if that's true, but it sounds reasonable.

Except it may not apply for super-low fpe's like the OP is using.  Maybe someone here knows?

[rsterne]

While 1 cc per FPE is great if you can get it, when placing a regulator inside a tubular reservoir, and attempting to get significant FPE, going as small as 1/2 cc per FPE may produce the best shot count, because it allows a larger HPA reservoir.... I would suggest that if 18 FPE is your target, you can probably stay closer to 18 cc, rather than smaller....

Bob