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Alstone · Moderator & Site Supporter

The general opinion is that to increase power on a Co2 gun is to increase the spring pressure or put weight on the hammer or both, after doing quite a lot of tests I have come to this conclusion.

To get as much gas into the barrel of a Co2 gun you have to open the valve for as long as possible the way this works is that the hammer hits the valve and pushes it in until the hammer hit the stop, this is the open time, immediately the high pressure gas behind the valve slams it shut, you have no control over this or very little. So if you can slow the hammer down you get more gas, fitting a stronger spring only speeds it up and the open time is shorter, but if you put a weight on to the hammer thereby increasing it’s mass you can use a weaker spring and the hammer can be made to travel a lot slower and still open the valve all the way, make sure the hammer still reaches the stop on a full capsul of gas. In tests on this theory I have had very good results, it is just a matter of balancing the weight against the spring power.

Any comments would be great fully received or if you think I’m talking out of my arse say so.

AL

AirGunEric · Site Admin

I think you've got the right idea, with one alteration- I suspect using a weaker valve spring without additional hammer weight would also allow more gas flow-through.

The other day I hogged-out the valve of a 1077, increasing the port size of both the valve head holes and the valve body hole from the feed tube. No changes to spring or hammer from previous alterations- and overall gain was minimal- around 3% improvement in velocity. The spring inside was extremely tight (it took a fair bit of pressure to re-seat the lock ring to hold it in)- so I'm betting using a weaker spring there would allow for a lot more gas flow to be required before the gas pressure would force the valve to close.

Of course- this may also depend on the particular valve design in any given gun?

Alstone · Moderator & Site Supporter

What I also found out was that a heavier weight on the hammer helps to stabilise the variation in pellet speed from shot to shot.

AL

AirGunEric · Site Admin

Hmm- I wonder if we could assume from this that some valves may not be optimally designed and each hammer strike with a lighter hammer may or may not extend the valve completely- but the added hammer weight or spring pressure allows a "dead blow" of sorts to force the valve to open more consistently- i.e. to it's maximum extended position?

I will still get around to trying a slightly lighter valve spring to see what occurs- but I won't have any time for this until likely next week-end.