You can get quite a bit more out of the Crosman 22xx valve. Just boring the valve cap and changing to a lighter spring will get you most of what is available from them. But for those of you who want to the maximum power output these steps will help.

To get the valve apart put it in a vice. Use a small pipe wrench or channel locks on the cap it does not need to look pretty on the outside. Like most things in the world it's what's on the inside that counts.



Parts that help a great deal are.

1- Increase the volume.

That's 25/64ths on the bit. I drilled down about 1/4” then polished it inside. The lathe was nice for drilling but a vice and drill or drill press will work fine.



Pic of the front of the valve cap. I have cut some of the threads off but left more than half for strength. I used a lathe on this one but used to use a hacksaw and some files to do the same job.



2-Lighter spring. Here are some lighter springs. The spring should be about 1/8" to 1/4" longer because the volume in the valve was increased by drilling that far into the cap. The spring will actually close the valve even if it is very light but gas can be wasted before it closes. I use one that's about half as strong. Too light a spring can cause damage to the tube and valve. Especially when combined with a heavy hammer spring. I have used two springs, slid together sideways then installed to get the strength when a single could not be found. The bottom valve has a bulk adapter cap that has been drilled for volume and modified the same as the stock valve cap.



3-Drill the exhaust port. The port hole drilled in the valve should be the same size as the ID of the breech seal used. 11/64ths or a #19 drill bit seems to be near the sweet spot for the .22 caliber. The intake port may be drilled also but with the increased volume it should not make much of a difference for the .22 guns. Larger calibers can benefit from a larger intake especially if they are tube bulked.



4-. Change the port angle

I think it was Mikhail that first did this to the 13xx valve on the Old and defunct Crosman forum. I picked it up immediately and used it on the 22xx guns gaining near 20fps with the 14 inch barrel on my 2240. Use a dremel to ease the port angle. Then polish it up with a thin strip of 600 grit sandpaper taped to the back end of a small drill bit or similar item and installed on the dremel shaft. That is polish the area you just worked on. Also polish the other area marked on the diagram. If this one is messed up, bottom arrow, the valve will leak constantly. It could be left alone without losing much at all but the more polished everything is the smoother the flow