Most of the Moisons I have encountered slugged rather large with the tightest one ever being .3095 diameter. in a 91/30 with a barrel in the 29 inch range I would want my pistol cartrige conversion to have plenty of umph and yet be closer to bore diameter such as maybe the .327 Federal or .32 H&R Mag to reduce any chance of a squib and would be for hand lapping the bore on an old milsurp until I could see my own eyeball looking back at me when I looked down the bore ( mirror bright ). Am betting those instances in which the adaptors seized in the chambers had either less than smooth finish in them and or some chamber pressure issues from those bullets slowing down alot before they made it out of the barrel. Just my thoughts here as am not a smithy but seems like pistol cartridges were developed to perform out of "MUCH" shorter barrels with the occasional buntline being the rare exception otherwise why are Contender loads listed differently in loading Manuals such as Lyman vs. standard rifle cartridges of the same calibre
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