The valve and the sear are worth copying.
The valve is just a stem sealed with an o-ring that is held in place by the internal spring that operates the intake seal. The sear is a plate that slides vertically. The valve itself could be used in a vertical position with the sear plate sliding above the barrel to build a single shot pistol.
Traditional looking stem that seals the chamber has a bump outside the valve and a 20 mm or so washer in the next chamber. That is spring loaded and has a rubber travel limiter bushing, then an end plate. The stem sticks out the end a short distance and it locked there by the sliding plate. The trigger lifts the sliding plate till the hole aligns with the stem, which blows out against the spring until the air is exhausted, and then the spring pushes it back in place, allowing the spring loaded sear to fall back in the way.
Only complaints would be that the safety engages the trigger, not the sear itself in the Cannon package, and people would scope them, then pump with their hand against the barrel, which was brass and floated in a thin plastic sleeve.
Less than five pounds without a scope, and it would do an honest 900 fps with normal pellets like the JSB Exacts. Adjustable trigger, push a button and the breach slid open, 850 to 950 at 8 pumps, tack driver accurate if you did not use the barrel to pump against or the scope, and it had real pins with clips, not roll pins. You just had to hold them by the wrist when you pumped them because of the floated barrel
I could show you a man that has been using one for over twenty years without changing o-rings.
Pyramyd Air has the schematic if you can find it. I looked at it a short time back, but could not find it just now. I have one torn apart sitting beside me. When I go out, i will take it by the paintball shop and completely reseal it.
My interest in the sear comes from the fact that it begs a set trigger setup. Using say, the old CVA Mountain Rifle type of set trigger, the sear can be set to an amazing amount of engagement for safety purposes, yet be used directly as a field trigger, or set and used at say 8 ounces. Nothing else needed with this valve.
Same size as a normal valve, drop into the barrel and lock it in place. Drop washer on stem, spring on washer, and rubber bushing over spring directly into the tube. Screw end plate on .
Drill a block vertically almost through the receiver and then at the last little bit go to a smaller hole. Drop a keyed rod in the hole and then a spring on top. Thread a plug into the receiver to hold the spring under tension. The plug also makes the spring tension adjustable.
Cut a notch in the rod for a safety to engage. You have just built the sear with a positive safety. Drill rod with one flat side, drilled through and then hardened would do the job just fine.
Now slide the tube into the receiver to where that sear holds the stem in the valve. You could even push the button and fire it by simply pushing up on the sear with your finger at that point. From there, the actual trigger lever you use to push up on it could look like many systems.
The Cannon receiver was a single block, but it is even easier to do a Crosman type breach on the tube. You would just have to end the tube against the sear, so the receiver would have to extend below the back of the tube at the end. Not a problem, since it is only about an inch from exhaust port to the end of the tube, so you need more space for your feed system and scope mount.
Since the bolt does nothing except push the next pellet into the breech, the spring loaded it like the old BSA breeches on the Techstars.
Make one out of good materials, put a real stock on , and make mine .22
If you install the sear unit behind the valve inside the tube itself, you only add a half inch or so to the length, and that means you could swap breeches like the Crosman stuff. Swapping valve volume could be done as easily as lengthening and shortening the valve/pump depending on the direction needed. The sear spring is easily adjusted or changed, and the engagement is just as easily adjusted. Need more flow? Use a bigger stem. Any spring loaded set trigger works, and can be mounted in the stock as with a longrifle.
It doesn't get any more simple, easier to make or light, and it makes real hunting power.
Make my tube a long throw so I only have to pump it three or four times, then put a solid breech and a 24 inch .22 barrel on top. No magazine or feed system needed. Let it bark, no pickle needed. Put that in a nice maple stock with a single set trigger. Alternately, make mine a long throw but shrink the pump bore, allowing me to achieve higher pressures at 8 pumps.
Can you tell that I am a fan?
Turn the valve around, plumb from a blind end pump, and a modern target style trigger can be used.
