Replied to PM, might as well post here in case anyone else wants to know
The extension was made for me, tis just modellers resin (iirc ) and paint though. Not terribly in focus, but here you can see it before painting. That lovely green ¬_¬ and the normal colour of the resin. Paint doesn't stick to it very well I have to say.
And nothing happens. The trigger has no mechanism really, it's just the force of your finger pressing the hammer down. A tanaka shell, on a complete fill of gas, has too much internal pressure for your finger alone to trigger the valve. Which means you have