Have you tried something a little heavier?
I have had excellent results with 165-168gr bullets in -06. Federal Deer Thug seems to be pretty good factory fodder.
I know you said factory ammo but a near max charge of IMR 4350 with a CCI BR2 and a Sierra Gameking HPBT is pure magic in a couple of mine.
Here's an article on torque tuning, wont cost anything and couldn't hurt.http://www.accurateshooter.com/techn...torque-tuning/
Good luck
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