Search the board on bore slugging to see how to find constrictions and throat sizes.
A bullet being "too hard" is neutralized by having the bullet sized large enough and having constrictions lapped out. The only instance in which a soft bullet is better is when pressure had to bump it up to seal the bore either because it started out on the small side or because it was narrowed by a constriction. If you don't have those two problems, the hard bullet won't lead more. Indeed, if your bore is smooth, you may find you can shoot them with no lube at all and still get no leading.
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