wyatttt:
A google search under heading of The Original 1000 Yard Pennsylvania Benchrest Club, or words to that effect, might come up with something of interest.
At one time, the club hosted a few prone matches, just lay down in the grass, with your rifle, I used a Model 70 Winchester Standard Target Rifle, in 30-06, and an old 1.25" wide military sling, and fire away.
Their range was near Williamsport, PA, and there used to be some strange mirages there. The wind was nothing like what one experienced as Camp Perry, as I recall.
Hope this helps.
I don't know what you are shooting, but one load that I used, in a particular rifle was as follows. 52 grains of IMR 4350, Winchester commercial brass, and Sierra 180 grain Matchking bullets, the older closed point type. I seated them to maximum length, about .005 clear of the rifling. Worked well for me. I estimated muzzle velocity to be approximately 2500 - 2600 ft/sec. This load grouped inside 2" at 200 yards, firing over a sand bag rest. Good luck.