New guy here. I have a 16 inch 450B on it's way and have already started gathering up reloading componets. As an avid bullet caster I cast about (pun intended) for an approiate bullet mold. I contacted Tom at Accurate Molds in S.L.C, Utah and he quickly came up with a neat design for this cartridge.
On his website catalog it is mold # 45-280D. Check it out. Drawings and specifications are on there also.
I have already ordered mine. I will report later on how it works out.