Rifles are funny things. I have some that shoot the lighter bullets just fine. Others demand a heavy bullet. My CVA likes a heavy bullet for some reason. 300 grain XTP, 405 grain Remington FP, 300 grain Shockwaves.. it just shoots them better.

Also, some rifles do not like sabots as well as conicals. Perhaps you have one of them rifles that likes big lead. All you can do it try different loads. If I had your rifle I would try several loads out of it...

Nosler 260 grain Partitian, 300 grain Barnes Expanders, 300 grain XTPs, 240 grain XTPs, 200, 250, & 300 grain Shockwaves, Speer Gold Dots, Maxiball, REAL conicals, ... and work all of them with different powders and charge strengths. Somewhere in that you will find a load that will shoot the way you want with the accuracy you need. Don't be so concerned about matching a 30-06 as you never will. Instead, develope a good accurate load, practice, set your scope to the distance you might encounter, and hunt accordingly. Put that projectile in the right place and let it do the work for you.