Could Germany buy Italian 15-inch guns for its battleships?
Short answerTechnically yes, but Hitler's prestige and preference for German-controlled designs make that solution very unlikely.
NotesBuying Italian 15-inch guns is treated as technically possible in this counterfactual. The explanation offered for rejecting that option is Hitler's concern for prestige and the appearance of national self-sufficiency. Scharnhorst provides the example of a ship for which this alternative was not taken. The same criticism extends to the failure to seek Japanese advice on carrier design.