Lets see, in addition to being undersize, the 9mm bullet will have to transit half the length of a .357 case completely out of contact with steel before slamming into one side or the other of the small taper leading into the chamber throat. It’s very likely to enter the forcing cone tipped a bit and not concentric with the bore. Does that sound like a recipe for bullseye accuracy to you?

You already know that variations in 9 mm canalures and rim thickness mean some brands will be compatible with moon clips and others won’t be. You may not know that trying to extract 6 steel cases like Wolff 9 mms will just bend your ejector rod. That rules out benefiting from the least expensive 9mm cartridges. The next lowest price 9 mm, bulk pack Remington and Winchester FMJ have never grouped tight enough to suit me in any gun. Do you really think you can save enough on ammunition to make up for the cost of conversion?

Paying the collector’s premium for a 9mm Ruger Service Six, Speed Six, or SP 101, or a S&W 547 or 940 could get you a fixed sighted 9mm revolver, but not the adjustable sighted revolver you want. Adding adjustable sights to one of them would kill their collector’s value. The 547 is not moon clip compatible and slower than most revolvers reloading with speed loaders because after the speed loader is dropped the cartridges still have to be pushed in past the spring loaded ejector tabs.

Back when some 9mm ammo really was inexpensive I wanted a 9mm revolver to use it in matches. It just doesn’t make sense when you look at it critically.