Which Hornady 75 are you using? The HPBT, or the ELD-M. If the latter, you should not load this bullet to mag length. It is a fine bullet for longer ranges, but must be run out long and single loaded.
I have run a lot of 75 HPBTs over 23.5 Varget with the SB small rifle primer and LC or TAA military brass. It is superbly accurate to 300m, and will hold up to 600. I earned a high master card and some leg points with this load. I've found the slightly reduced load from max to be a touch more consistent in my rifle to 300m which is the primary distance I fire this ammo loaded to mag length. I use the 75 ELD-M over 24R15 for longer ranges and single load them. I'm shooting a box stock RRA Natl Match A4 20" 1:8.
I wouldn't sweat the velocity much, if you do, you maybe should have considered a 20" or longer on your build. 2650 with a high-b.c. bullet will hold up well to 600 yards, may just require a bit more dope. Faster would be ideal, but not at the cost of reduced consistency. By all means, test the other suitable powders in your inventory. CFE223 is known to produce higher velocities. Consistency according to other shooters has been mixed. Some good, some not so much. Other powders commonly found on the line of high power competition with the 5.56 and 75-80 grain bullets are R15, H4895, and Viht N140.
