the 458 socom is a rifle round developed by Marty Ter weems of teppo jutsu (translation is "Art of Rifle") It sends a .458" 300 gr hp downrange from a 16" barrel at about 2100 fps.
The parent case is a 50 AEmagnum stretched from 1.3 to 1.7 inches, necking to 45 reduces case length to 1.585. the rim is rebated to standard 308 size.
Now here's a pic of my 458

oh and another
Now the bushy fires a .452 dia. bullet, so unless you buy those hornady muzzleloader slugs, your left with pistol bullets if ya wanna reload. the 458 uses standard .458 rifle bullets from 300 to500 gr.
RR