TAC is 87 on the burn rate chart, IMR 8208 XBR is 86. Benchmark is 81. The lower the number the faster the burn. I'll try TAC and Benchmark both.
P
Don't put too much faith in the burn rate charts, but they are useful as a general guideline and figuring out which powders might be appropriate as you're doing. The difference between 8208 and Benchmark in that example can be just the lot to lot difference.
TAC is good for another 100-150 fps faster than 8208 with that bullet, but you may or may not find a good accuracy node with it. I really like TAC and XTerminator for a lot of loads, and use it exclusively for 50 and 65gr 5.56 AR15 loads, but didn't find the accuracy I wanted with the 75/77gr bullets. I don't like to give up 150 fps if I don't need to, but in my case Benchmark & 8208 made enough difference in accuracy to be worth it. YMMV of course, especially since it sounds like you're using a different (223 Rem) chamber.
BTW your load of Benchmark (23.5gr) should be right on, that particular load (well, 23.4-23.6 gr) with a 75gr Hornady has proven very accurate in a bunch of different rifles, and others online report the same thing.
One other powder that some really like in the 223 with 75's is Leverevolution. It does produce some impressive velocity, but I haven't worked with it enough to talk about it's accuracy potential in that combination.
