I don't guess that a spirial magazine can be retrofitted to a 336 rifle. There must have been some internal differences in the action for the rifle to feed from this spirial magazine. How complicated would it be for a smith to make up a spirial magazine? Seems this would open up a lot of different caliber possibilities.
Having restored a junker Remington M14, I know that it is possible to find spiral magazines in the various calibers. I also believe it would not be too difficult to fit one of those mags to a M336. I will check the magazine (for a .32 Rem) that I have and see what the possibilities are.
