I am not a pro but the length of the bullet is also important for twist rate. If your shooting a ar I would load Hornady 75 hpbt and if it’s a bolt gun you could try the 75 eld match. Generally speaking 68 to 75 grains is where you want to be.
It may depend (a little) on elevation, but then again, I used an 8.0 to go Distinguished with what was maybe a marginal combination with the Berger 82. Stecker said it would work, and so it did.
You may not like this, but those of us strongly in the know about .223 at 600 and under tend to run two loads. There are multiple reasons for that.
If you are interested in strictly precision at 300 yards and under, then the 69 Sierra MatchKing, the 73 Berger BTHP, and the 75 Hornady BTHP come to mind. They are NOT wind runners as much as some bullets, but they are tolerant of jump (which you will have), and in moderately tight twist rates, they settle down very quickly, which some would suggest results in smaller groups at short range. Sometimes the 77 SMK, 77 Nosler, 77 Berger, can be made to run really tight groups at short range, but I've not seen them tighten up as much as the previous bullets.
When you get to 400-600 yards, wind gets to be not-so-much-fun, particularly since the cartridge is pretty damned anemic as it is. From there and out, I recommend no LESS than 77 BTHP, and if possible, one of the tipped 70-class like an ELD, OR....and this is preferred....a Berger 82, or Sierra 80.
The decision on what one of those to run is determined by whether you want to feed from mag (depending on mag), or whether you are okay single-feeding the long range ammo. The 80s are really too long to magazine load for most magazine types without taking up too much powder room and losing the advantage over the 70-class.
Now. Loaded OUT at the lands of a decently-long chamber like a Wylde or WOA, the 80-class bullets can have as much or more powder behind them as a 77 magazine bullet, but boost BC in a significant way. AND, despite the typical assumptions about grain weight slowing the bullets --not true, by the way--the shorter bearing surfaces of the slick 80's can allow them to move at about the same speed as 70-class long-bearing bullets. Kinda handy in a 9-13 mph crosswind at 3-4 o'clock.
Now what I said about short range precision with the 69-75 bullets is not necessarily gospel. When tuned, the 80-class loads of mine have shot in the 4's with even A2 irons. Probably if I had been scoped, those were under 1/4 Minute loads in those two uppers.
In some fashion, I guess you need to answer for yourself: "How fast do I want to go?"
My 1:8" twist barrels are 24" long, and I also have a 24", 1:9" twist barrel. They all shoot the Hornady 75gr HPBT Match bullet well, and I have used them in competition out to 600yd. My loads vary from 23.5gr of Varget to 24.4gr of Varget. CCI BR-4, in Winchester, Starline, and Prvi-Partizan (PPU Headstamp) brass.
Next up is 100yd load testing between 23.5gr and 23.7gr of Varget, along with IMI 77 Razor Core and Hornady/Frontier 75gr HPBT Match factory loads. Right now, we have a lot of wind and Wildfire cautions throughout the area, so it may be awhile before results are available.
I will also be testing these loads in a brand new 16", 1:7" barrel, just as a feasibility study. For future testing, this will be my "generic rifle" platform for ammunition testing.