Thanks, i'll get some measurements/refresh my memory and let you know what i think. I bought the blue New model back in the late 70's early 80's, then i saw a 9mm stainless cyl. on ebay (30 years later) and bought it on a "lets see if this will work" kind of approach. It fit! all chambers align w/bbl using gauge rod. started loading 9mm and found some were too long and i could not rotate the chamber as the case head interfered with the breach face lip on the frame. I thought it may have been the chamber depths. But after reading your posts it re-lit my interest. Both cylinders OAL measure 1.978 +/-.003".
After reading your post i checked the BCG's .357=.005.
9mm=.012 +.001/-.000.
So if i machined .008 off the small protruding front cyl. bushing.... math would say i would reduce my BCG to~.004" and increase the space behind the cyl. (between the rear face of cyl. to the frame breach face) by .008" which may be enough for the cases to index properly past the "breach face lip".
My concern, perhaps unfounded due to the linear forces when firing, and the (space filled with the case heads) is the "new" .008" gap at the rear between the index star and the frame.
Is there any end shake concerns? I think i was hesitant to shorten the cyl. length without fully knowing what i was doing.
Thanks for restarting my interest!