Kiwi,
I still think you would need to have the EL "in hand", to know what would be required to fit the muzzle end,depending on the particular EL,it's possible that no work would be required.At the breech end, in addition to the locator slot in the main extractor, most ELs require a "flat" area to be placed in the shotshell rimrecess.This is for a headspace adjisting screw.The locating slot is usually just filed and the flat is placed by hand with a tool that looks similar to a "spotfacer", held in place by a fixture that duplicates the rear end of an EL.If you only intend to fit one, I would think you could do a satisfactory job with a scraper.You are right that the more powerful cartridges can only be fitted to certain actions( usually o/u), but this is different than the possibility of having to "bush" the firing pin.If I were you, I would try to avoid sending a gun to Germany to have the EL fit up, as this would be a real "exercise".
Mike
