I have the same barrel as you got, and mine loves 30-30.5gr Varget. I usually shoot 87gr vmax with that load @ .015" jump and it shoots 1/4" groups, but will shoot the same charge with 105amax very well also.

I would stick with the Varget. I havent seen a 6br yet that didnt like Varget, and alot of people will say if you cant get it to shoot Varget then it wont shoot. Just do some reading over at 6mmbr.com..

On some groups it looks like you almost have two seperate groups(3 and 2). Id pay alot of attention to your cheekweld, trigger pull, and hold the gun the same every time. I try to not even put my other hand on it and just let it recoil.

Is the bench real sturdy? Reason I ask is at my range there are a couple benches(wooden) that wobble and are unlevel. It drives me nuts if I get there and have to shoot off them.