OK, my craziness got some work done.
I gave the whole thing a good night of slee.... äääh thoughts, and without any fear regarding the clear and present danger, i put it on the lathe again - for the new planned design:
two steps, for a better fit.
Then turning the barrel:
This slides over the receiver:
And the adapter for the flashhider:
A simple piece. (I reused a old delrin flashhider, cause i had no other delrin in the right dia)
The ready parts: