you could get one made up out of an old crownpoint to cocker threads, plenty of meat for the threads.
other option is to get a micromag body (yum) cocker threads as standard.
failing that ive got lots of mag barrels... what do you need?
Only place your get one is stateside try www.automags.org
docs adapter is what u need or get one mase over here
I made one before but is now owned by @Gee Tee