What 7mm magnum cartridge to build?

[Kcollins01]

7 PRC is a Sweet choice,.. My son, really Likes, his !
5 shots under, 1/2 MOA with, 180 grain, ELD-M's / ADG Brass at, 2,987 FPS with, "Thrown" Charges of, StaBall HD powder.
7 SAUM is,. another good, choice.
I'd AVOID, the Barrel Burners that, GULP,. Huge Volumes of, Gun Powder !

That's what I'm wanting to do with this build something a little more efficient

 

[Idaho Lefty]

BEFORE Building / Re-Barreling a Rifle, I'd BUY some, GOOD Brass,.. FIRST !
ADG brass,. if, you can Find it, "Works" Good !
Then Dies ( I personally Like, Forster Dies )