Re: 1000 yard load
I started with heavier loads, but learned over time that the gun was happier, and I was happier, with lower charge weights.
42.5 grains of Varget under a 175 bullet happens to be my 1000 yard load for the .308 and it's the best one I've come up with in the 5R that I shoot. My buddy uses 41.5 grains, but has a barrel that's five inches longer than my 5R. Both loads shoot great at 1000 yards.
Heavier charges yielded no improvement in performance, except on very windy days, of course.