Re: 1000 yard load question
I shoot my Service Rifle at 1000 yards. My load is 24.8 grains of RE-15 under an 80 grain Berger. These are stuffed into Winchester brass primed with WSR's. The brass is once fired, and from the same lot. It is massaged with necks trimmed, flash holes deburred, and primer pockets uniformed. Bullets are seated .010 off although Berger recommended .010 in. The key is consistent neck tension round to round for a low ES and SD, which is essential for success at 1000, as it better assures hits at adjusted elevation where the target bullseye is its widest. Holding to that elevation helps to prevent lost points to wind when you do not properly counter for wind effects. BTW, my average muzzle velocity is 2800 fps which keeps bullets stable to 1000.
I'd rather shoot an iron sight AR based Service Rifle at 1000 yards rather than anything else. My average score is only 93 percent so far, 5 points below my overall LR average; but, the challenge of it all makes it much more compelling.
Also, holding to exacting elevation with the Service Rifle's post front sight requires extraordinary picture memory, and even with such memory the target may still be so vague as to not permit exploitation of the picture memory asset. In that scenario, I may use a frame hold or some sort of hold on the number board. My point here is even though you may not see much of a target do not let that distract or defeat you as there's often more than just one way to skin a cat.
Another thing, shoot during the prevailing wind, you do not have the time to be making massive sight adjustments and you cannot accurately favor, so adjust windage initially to what's prevailing; and, if possible, hold up until prevailing wind comes back. You can read the wind at mid range where it has its greatest effect by setting your spotting scope focus a 1/4 turn counter clockwise from target focus.
Lastly, remember since sight misalignment creates angular error increasing with distance, be sure to align your sights before adjusting NPA to the hold you're seeking. And, of course, call your shots and plot strikes; and, use your score book's MOA grid to help you do shooter/target analysis, after all, you don't want to be chasing your shots from having adjusted for non existent wind.