I might be shifting gears to build a .458 Socom whisper rifle. I notice the ammo is out of sight (don't have too many big bores) so I would reload. I also happen to own a cnc lathe and considering machining my own bullets. Also being an aerospace engineer, I would take the design pretty serious. I am just curious what the preference is on bullet compositions. I am leaning towards solid copper or bronze but I would really like to inject lead in a perfect world to get my density up. I am not as concerned with an "exploding" round (mushroom, frag, etc), I am primarily working on a round that will be accurate at out over 200M. I might later design a bullet with a ballistic tip.