For all my .308 loads I use Hodgdon Varget powder. Seems to be better about temp swings than some of the others out there.
Also, for 175's, I load with 44.0gr of Varget. Same for 168's. But your rifle might like less. I would try working your load up to 44.0...Starting around 42.0, 42.5, 43.0, 43.5, 44.0 and shooting 3-shot groups of each to see which one your barrel likes.
As for primers I'd use Federal Gold Medal Match 210 primers, also known as Federal 210M primers.
I also use Lapua brass, but it's kinda pricey, but excellent brass that will last a long time.
If you are getting that good of resultts with factory ammo it might be an arduous task to work up a load that accurate.
I shot a 24-shot group out of my factory Rem 700 5R, that measured 1.37" @ 100 yards, with Nosler 168 Custom Comp bullets, 44.0gr of Varget, Federal 210 primers, and Lapua brass. For me, that is my winning combo.
But every rifle is different. So what works in mine might shoot horribly out of yours. You just have to tinker with it and see what works best for your gun.