1/9" or if you find 1/8"
you can use bullet from 52 grainer until 75 grainers with a 1/8" barrel
my best shoot : bullet Match 69 gn / poxder VV N550- charge 31 gn / Savage 12 BVSS 1/8"
at 500 yards
Just care of the chamber of the rifle
Ruger rifle precision is not a Savage.... :)
I'll try different brass ( even Lapua SR ) and I keep the Norma , for me they are the best
You can see than your reload are up of data base of VV
But friends of mines with RPR 6.5 CM reload until 44 gn for mid range
My best reload for 300 m ( 325 yds )
N160 : 38.3 gn / primers Fed 210 N / bullets Hornady Match 140 gn or Lapua Scénar 139 gn
Soon I'll try the new Hornady ELD 142 gn