9x23 steyr or 9x25 mauser?

[Jim Watson]

That was my thinking.
You will need a good extractor to fit down to the small rim but I THINK that will be feasible.

 

[justin22885]

a 22 TCM extractor will work, its designed to fit the 5.56/.223 rim.. heck, if i could find a 22 TCM slide that would work better but those are much more rare to come by.. but yeah.. shaving down the inside of the extractor to bring the claw in further should work.. works on my AK-74 converted to 5.56