Oh, powder?
Again, try different powders to see what your rifle "likes".
My best 45 grain groups ever used IMR4198. Terrible metering powder (have to weigh every charge if you want consistency which equals accuracy).
My best 55 grain group ever used IMR4198.
I have found that the right charge of BLC2 will give very nice groups also. I'm using a lot of that powder now and it meters like water. Very consistent.
H335 meters very well, too, but BLC2 gives me slightly better groups.