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CO2 valve question? Answered

Hi ...

I would like to ask for your opinion about my idea :

I got as a present a CO2 airsoft pistol. Unfortunately it's too powerful for the UK airsoft norms. So I would like to make it weaker.

I took the magazine apart and I had a look at the valve. I find out, that the moving part in the valve (that release the CO2 from cartridge to the gun) is able to move cca 2mm. Now my question is : If I would limit the movement with "something" so that the moving part woudl move only 0.5-1mm ... would this make the gun weaker ???

Thank you for your opinion or any suggestions.


Use a stronger valve spring (or a weaker hammer spring, or both). It's much easier than trying to limit the travel of the valve pin.

And could give a small advice, how to get a spring that would fit all the dimension and tensions ???

That's why I wanted to put a small piece with the spring, which (in my theory) would make the spring harder - less CO2 - weaker gun.

But I have no clue where and how to find the spring ?!?!

If you just want to put in a shim behind the existing spring to increase the compression, that would probably work just fine. I used to mod my paintball guns like that with little plastic washers I cut out of old bottles.

Assorted springs that might work can be found in the little bins at many hardware stores, or maybe inside a ballpoint pen or a kid's dart gun, if you're lucky. Depends on what size you need.

If you're bothered about law you would have to get the thing reclassified, and I doubt that would happen.


I know :( ... but to be honest, so far I care about the site rules. My pistol gives about 370 FPS ... and the maximum allowed is 350 FPS.

So I would like to make it weaker.

site rules don't matter - it's a fair question, but in legal terms it would need certification.