Well that was easy enough.. again, the dimensions are bound to be incorrect, I'm just working off guestimates here.. I modified the push rod, it's now double the diameter of the original design. 4mm, that's about 1/6 of an inch - I don't think it'll bend when pushing the hammer back. I also added the O-rings here..
Hmmm, interesting Akumabito. This concept of your would certainly avoid heavy modifications to the revolver. Except the lockwork for the trigger still has to be modified so that the hammer stays back and locks at full cock while the trigger is still depressed. Then when the trigger is released, the trigger resets and is ready to drop the hammer when the trigger is functioned again.
My main concern about this concept is whether the O ring will make an adequate seal between the gas hole in the barrel and the gas hole in the gas cylinder? I've been "bit" before from the flame and bits of burning black powder coming out between the barrel to cylinder gap. It even cut the cuff of one of my shirt cuffs once on my off hand when I wasn't careful enough to keep it out from under the barrel to cylinder gap area.
So I know how that force can cut. It can even eventually cut metal after repeated firings. I've seen flame cuts on the underside of the top strap just above the forcing cone of well used revolvers from that flame cutting force.
I couldn't say absolutely for sure without seeing it tested, but the probability of that O ring between the gas hole in the barrel and the gas hole in the gas cylinder blowing right out or being blast cut into worthlessness is very high.
That's a shame too, because except for that your arbor pin/gas cylinder has really good potential and like I said, just for itself, requires very little modification to the revolver except for drilling a gas hole in the barrel and modifying the lock work for the rebounding hammer to stay cocked while the trigger was still depressed until the trigger was released to reset it for the next shot. Now if there were just some way to seal those two gas holes at the junction where they come together more effectively without using an O ring....
I thought about something like this. There is a front plug for the gas cylinder screwing in to block the front of the gas cylinder.....before you install that plug you insert a cone shaped piece into the front of the gas tube. That cone piece gets pushed up into the gas hole and is forced up in there (like a piece of flared copper tubing gets tight in a plumbing line) when the plug is screwed into the end of the gas cylinder. Once that cone shaped piece is inserted upwards into the gas hole of the tube, the front plug being screwed in wedges it up there tightly. Forming an effective gas seal. Then as it comes out of the top of the gas tube, that same cone shaped piece is forced into the gas hole in the bottom of the barrel tightly by that same front plug being screwed into the gas tube.....so it also is gas leak sealed against the barrel like a piece of flared copper tubing being tightly wedged in plumbing.
The only problem with that idea of mine is that even if it worked, it would be difficult if not almost impossible to take back apart again to remove the arbor pin/gas tube to take the cylinder off. Because once the cone was wedged into place in both the gas tube and in the bottom of the barrel, it would be very difficult to remove with this tiny small cone being inside the already small diameter arbor pin tube, jammed upward in that tube into the bottom of the barrel.
We have to find a way to effectively seal that gas tap junction without using an O ring Akumabito, and one that can still easily be disassembled. Then it might work. Perhaps something as simple as a threaded rod drilled with an L shaped gas hole in it
screwing up from the bottom of the gas tube into the bottom of the barrel which would form an effective gas seal juncture between the arbor pin/as cylinder and the gas hole in the barrel. The threaded rod could be unscrewed so it disengaged from the bottom of the barrel to allow removing the arbor pin/gas tube, so the cylinder could be removed. You do better renderings than I can Akumabito, could you render up something like that?