Quote Originally Posted by zacii View Post
Doesn't the 450 BM use .451" pistol bullets, and the 458 SOCOM use .458" rifle bullets?
Both ~may use 45-70 as well, provided they can be ran through a re-sizer, Lee taper crimp 45 ACP die (#90785 ?). More so for the 450BM.
A multitude of grains to choose from, provided appropriate seating depth / LOA.