2240 Valve mods

Hello all,
With a 10inch Barrel, are there any mods I can do to the valve itself?

Cheers

Kris

Yea, I think that smoothing off the path of the CO2 by taking a dremel to the transfer port will help a bit, but don't think there's a huge gain in power, still an increase is an increase.

Thanks


KrisNZ

So i been looking at 2240 valve on line out of curiosity,
It would seem you can buy a better flow valve from boss. A better transfer port to barrel, up to 25% increase in volume flow claimed. Also a stronger hammer spring to keep valve open longer or weaker valve return spring.
Seems the longer barrel is the number one thing to do.
Im assuming as co2 will only pressurize to a certain pressure (not taking heat and cooling affect into account) that goal would be to get enough co2 into the barrel to keep it expanding for the duration of the pellets travel along the barrel.
Thus there will only be so much that can be achieved in actual power gain and that max power is created by having a long continuous push that doesn't stop till after the pellet leaves the barrel. Not a get the pellet going and let momentum carry it the final part of barrel, or a weaker push as the co2 slows its expansion due to decreasing expansion pressure.
Only issue i see would be the gas flow around the pallet as it left the barrel. Your crown would want to be in good nick to encourage even distribution of escaping gas so as not to upset the pellet.
It would also seem you can actually take some metal out of the head of the valve to help volume.
Also the thinning of the valve stem as mentioned above.
Nut as i say, this is from web research.
Hopefully the ppl on here who pull these co2 pistols apart can verify this

If you want to the math for the volume of your barrel here's a blurb on expansion rate
The liquid-to-gas expansion ratio for CO2 is approximately 535:1. This means that for every unit of liquid CO2, it expands into 535 units of gaseous CO2 when vaporized at room temperature and normal atmospheric pressure.

Heres a pipe volume calculator which you can get an approximate volume off. Due to rifling its not going to be exact but should get you in the ball park. It will take mm and inches at the same time so you can do the pellet in mm and barrel in inches
https://www.servicetitan.com/tools/pipe-volume-calculator



Edited by kruzaroad - 09 Jun 2025 at 2:44pm

I think a 12-14 inch barrel is the best to use with the modded valves,

kruzaroad wrote: The question would be, i think is it putting out enough power as it is to do what you need it to do.

Yes, your dead right.
So in my case modifying the valve would be of no real use.

Thanks

Kris