I just went through this myself, updating/modernizing a MK12.
The heart of the rifle is a Douglas SPR 1:8 SS barrel. V Seven upper receiver, V Seven 16.5” Enlightened Rail, Nightforce 2.5-10x24 in an A496 mount. Geissele SSA trigger, Dead Air Keymo flash hider and a SOPMOD stock.
Is it heavy? Yeah, kind of, sitting at 9.75 pounds. It does what I need it to do, it’s accurate, fairly smooth shooting, and it handles heat well.
My next updated rifle will be a RECCE. Almost same setup as above except using a V Seven 16” 1:7 SS barrel.
https://i.imgur.com/Nh9pzwt.jpg
https://i.imgur.com/MUJBL9I.jpg