Best cast bullet powder for 30 06

Those ten targets were shot at 50 yds. they were all just a random selection of powder charges that amounted to about 2.0 grs. above the Min. charge weight and 2.0 grs. below the Max. charge weight with a given bullet weight.  Honestly I was just trying to gather some data to find some good starting points to work up some low, mid, and upper range loads that might shoot well in the rifle.  Basically all the above load were just a shot in the dark based on my years of shooting cast lead bullet in a variety of rifles and actions.  Around my neck of the woods, 100 yds. would be considered long range.

My rifle is a stock Remington 770 everything is as it came from the factory except for the cheap $50 scope I put on it. I like the higher magnification, and it seems to be holding zero and the turrets are pretty repeatable the past couple of years I've used it.

Not sure what you mean by load refinements, basically I just FL resize all my brass and trim as necessary, I don't do anything special to the primer pockets except clean them.  I try and stick to one particular brand of brass when I work up a big batch of ammo, but I have multiple brands of 06 brass and I haven't found any issues like flyers with a given load using mixed brass.  Primer are just standard CCI LR or Win. LR.

The two bullets used on the ten targets were the Lee .309" 170 gr. FP and the Lee .312" 160 gr. TL RN bullet.  Bullets were cast from 50% pure lead and 50% COWW and air cooled from the mold. The bullet used on the first target I posted was the NOE 30 XCB cast from the same alloy and air cooled from the mold as well.

The powder coat I use is either Eastwood or powders I get from Smokes over at the CB's After coating and curing I water quench the bullets to add some additional hardness, gas check and size to .309" and let them set for about two weeks before loading. I use a NOE two-step case neck expander before seating the bullet and finish it off with a med roll crimp.