It's been a while since I updated this blog.
Here are some pics of the cylinder head I've made for your favorite springer rifles. I've made some improvements on the design, like fabricating the unit from stainless steel. I've also added a 4mm o-ring at the base of the nozzle to provide some damping. Sealing was also improved by adding another o-ring at the other end of the threaded area.
Notice the enlarged hole at the base of the cylinder head on the second picture? I've designed a spring-loaded valve that would fit in that tiny hole, which would serve as a gate which will open when the right pressure is reached. I'm calling it the V2B - Velocity Booster Valve.
More pictures can be found here