If you came to me with this project, this is what I would recommend:
-Fully accurize bolt and receiver
-fit an aftermarket recoil lug, I recommend Holland Comp recoil lug
-Lilja barrel contour for a rifle intended for +1000 yard use, AT LEAST a #7 contour with a #8 being even better.
-With the Berger 180s, go with the Lilja 1-9 twist 4 groove rifling.
-Go at least 28" barrel but no more then 30"
-Freefloat barrel obviously
-Install at least a Wyatts 3.820" extended internal magazine box of if you want to seat the 180 gr to the base of the neck, you may want to go with a Seekins 3.900" DM system or a 3.990" center feed Wyatts internal mag box.
-make sure stock is up to the challenge.
-Use a quality muzzle brake
, you will be happy with a good brake, no recoil at all from the 7mm RUM, the big 7mm really makes a good brake work very well.