The other thread about a 9mm speed six made me think.
You see security six cylinders on ebay. If an extra cylinder could be picked up cheap. Why not convert to 9mm?

How did the extractor work on those old speed sixes?

Know that boring and fitting the cylinder chambers is not part of the discussion.

You would have to use moonclips for the rimless cartridge conversion to extract.  If you can get an extra cylinder send it to TK Custom and they will do the work of rechambering the cylinder.  You can do 9mm or 38 Super.  The 9mm bullet is 0.355, 38 Super .356 and 38/357 Mag is 0.357 so the barrel are usually a touch big.  Most people find that as long as you shoot relatively heavy 9mm bullets, to increase the bearing area, accuracy is still very good.  If you reload then you can simply select bullets of a diameter that work best with your barrel and cylinder throats.

http://www.tkcustom.com/content/machine.asp  (scroll all the way to the bottom for ruger conversion prices)

Thanks for the link. I can machine the cylinder. Would have to buy the moon clips. Doubt I'll do it. Would be fun to do though.

Trying to picture making the dies to press out my own moon clips.