Lots of plated bullets available in 458 so good cheap options there.
One thing I found out on the 458 Socom is that there are two reamers that are used and they are slightly different. This can cause issues on some factory ammo as I recall. I used a Wilson Combat barrel before I knew there was a difference.
Some details here:
https://www.shootersforum.com/black-rifles/184017-458-socom.htmlRelevant part of the thread: "Go with TROMIX. Tony Rumore is one of the originators of the round, along with the cartridge designer Marty ter Weeme of Teppo Jutsu. They use the original spec reamer (as does Rock River, SBR, and SSK, along with the Saturn barrel sold by Brownell's) while Wilson Combat and ALL others uses the knockoff PTG reamer which was reverse engineered to get out of licensing fees to Teppo Jutsu"
I found useful info here:
http://www.458socomforums.com/