450. Sizing was one of the reasons I suggested contacting John. He often has bullet moulds for producing non-standard diameters, but doesn't list them on the website. At the least it would be worth a call or email to see if he can do .459 or .460. If he doesn't have them, nothing lost.

As to hardness, that's where we come up against competing properties of the lead alloy. The alloy must be hard enough to take the rifling and to hold its shape when penetrating the target. At the same time it must be malleable enough to obturate in the bore. It must also hold together and not shatter on impact. Typically lead alloys for use in bullets are a mix of lead and tin. The tin gives the hardness. Too much tin creates a brittle bullet which will shatter on impact. An alloy that also contains 4-6% antimony can allow for a harder yet malleable bullet IF you also do a heat treating process. Trace amounts of arsenic can also help. But all of this involves getting into custom alloys, casting yourself and a lot more work.