The reason I think you want the front of the valve wide open is twofold...
The Philippine co2 guns with no front end to the valve at all, make great power...more than anything else I've seen on co2.
It seems to me that when working with lowish air pressure, ANY restriction to flow upstream of the valve head reduces the average pressure of the charge delivered during valve dwell, and the key to getting good power with decent gas consumption is keeping that average as high as possible. Even your conical spring may be messing with peak flow..it's in the air stream.
Head diameter is a huge factor, tiny changes make noticeable differences..seat type not so much, in my experience. The undercut head seems to be the most reliable seal.
On my most potent QB, I used a section of 1/4" nylon air line; it's a few thousands bigger ID than the poly tube..then an oval twin port in the barrel above that..that may have helped
You might consider a longer wire probe. I haven't done a lot of experimenting with length, but my feeling is that with short dwell and lowish pressures, putting a larger percentage of the charge past the port helps.
I'm like you, in making more than one change at a time....it does make it tough to pin down what happened.
This message has been edited by classicalgas on May 28, 2012 1:55 AM This message has been edited by classicalgas on May 28, 2012 1:55 AM
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