In my Joseph Hambrusch 7x65r combination I get goid groups with RWS HIT factory ammo - 140 gn copper bullet. I also use 51.5gn of IMR 4831 under a Hornady 139gn softpoint and 50gn of IMR 4350 under the 173 gn H- Mantle.

All shoot well under 1” groups, bit barrel has to be cool and allowed to cool between shots.