I recently wasted a whole bunch of time on a 21" 7prc. Started out hoping to run h1000/175eldx but accuracy suffered with this combo. Ended up shooting 8-10rnd groups each of;
H1000, n565, n570, r26 and a couple r23
175eldx,180eldm, 175eh 180hyb.
N570 upper 2900's fps was achievable if you want to deal with vibrating/compressed load. Accuracy and es was not good in my barrel.
-H1000 primers were flat at 2800fps, not great accuracy
-R26 with had good accuracy, 2900+fps and best average es
-N565 was the most accurate with all 4 bullets, decent es at about 2860fps
-R23 had low velocity and poor accuracy
Any combo of n565, r26 180eldm &175eh would be fine for my rifle. R26 has better velocity and es while n565 has the best accuracy.