That long shank will likely drive up pressure. I'd probably go with a case bullet designed similarly shaped as the factory FN 350gr. The 350 pictured looks like the Speer 350gr., unless Hornady has changed their bullet shape again. If Speer, it won't expand as they have a 1/16" thick jacket designed for the .458 magnums & must be driven over 1,900fps or 2,000fps to initiate expansion.

The 350gr. Hornady RN - or better yet, a 300gr.FN or HP by Hornady, Rem. or Sierra would make better choices for a deer bullet, imho.

Veral Smith of LBT will make you a DC mould very reasonably priced and in the design and diameter you desire with whatever alloy you tell him. He's good - reasonable and knows cast bullets.