Get it punched out. you'll have a lot more case capacity to work with vs. 458 win.

for rings an bases, i'd suggest talley or one of the more expensive EAW/Recknagel swing-off or claw-type mounts. (let your budget decide for you.) But I'd definitely reccomend the talleys over the leupolds.

I cant imagine that you could possibly shoot enough 458wins in your gun to do any damage. You can load up/down the lott to suit your taste (both below and above 458 win performance).

Personally, i wouldn't bother with any 458win ammo or components. Just know that it has the capability when somethings gone wrong and you've lost your lott ammo.