Overall design layout is similar to the Air Force rifles, with the striker being propelled toward the rear.
It's knock to crack/blow open with the step on the spool (hopefully) providing a degree of self regulation similar to that found in typical poppet valves (hammer valves). A spring can be added to aid in regulation should that be found necessary.
The rear block (seen on the left) is to be threaded to accept paintball type tanks...co2 or regulated hpa. Hopefully length of pull won't become an issue.

Have yet to decide whether to countersink some more shcs to retain the rear bottle mount block or simply thread it...leaning with threads.
It's not going to be .22 cal.
