...so how do you come up with brass for the .375 SOCOM? That would be my biggest concern.
Neck down .458S.
Starline...
https://www.starlinebrass.com/458-socom-brass/In Stock... I am sure someone will split a K with you.
Also 458SocomForums.Com has a .375S sub section... Member "Big Bore" is great on TRUTHFUL Socom stuff
This Link500 yards is the outer limit for .375S in my opinion... 400 minus is ideal.