The mods herein may cause over 500 fps performance.

After I got my shiny new flat top piston and valve from Eric and installed it, I thought; well that works. What else?
Being leery of chopping up the new valve, it ocurred to me that I might have an option. I had this lying around cluttering the place up.
Valve.jpg

Why not take off the point, I thought.
Pre Saw.jpg
Actually, my first go, I walked past the bandsaw and got out a hacksaw. It worked OK, but wasn't quite straight so I filed it to make it worse.
The bandsaw is certainly better.
Post Saw.jpg

Then, of course, more volume might be good.
Volume.jpgPost Volume.jpg

The results look pretty good.
Done 1.jpgDone 2.jpgDone 3.jpg
This worked well in the gun and improved performance. I thought that it would take more pumps for the same output, but would have a higher maximum. As it turned out the number of pumps weren't that much higher for a given velocity, but at the top end I got a better maximum velocity.

Well, that just begs the question, what will more volume do?
A friend with a lathe faced the flat top for me and while he was at it he bored out the ID. As it turns out, he got too close to the shoulder at the end of the male thread and...
Too Much.jpg

Fortunately, I still have my commercial flat top valve to use. I also have a couple of other stock valves, as I have been doing some mods for relatives (Eric could tell you I have enough spare barrels to make a wind chime).
If anyone wonders, the extra volume from boring didn't seem to make a huge difference.