In F-TR, there are not many shooters using a .223 Rem at 1000 yd, especially ones that end up on the podium when the matches are finished. There are a couple reasons for this that include the much higher BCs of 200+ gr .308 Win bullets, as well as the issue about which you're inquiring. F-Class shooters often throw these ES/SD numbers around in various discussions, and almost by convention are usually referring to values obtained for 5-shot groups, just to be clear at the outset. There are a number of reasons for this, including the fact that shooters are not allowed to record muzzle velocity during the matches, and the fact that 5-shot velocity data is usually at hand from the load development process.
I have run .223 Rem bolt rifles in F-TR for many years. My competition loads during that time have always consisted of H4895, pointed Berger 90 VLDs, Fed 205 primers, and Lapua brass (un-turned necks). I've won a lot of matches shooting that combination, including the 2015 CA State Championship at 1000 yd. Acknowledging the obviously statistical limitations of 5-shot groups, what I can tell you is my very best loads will generally fall somewhere in the range of 15-20 fps ES, 5-8 SD. Average to mediocre statistical values would be more like 20-25 fps ES, 8-12 SD. Obviously, those numbers only get larger as the shot string length increases, but they are data of which I have the most, and am most familiar.
What I have found over the years is that everything matters in the small .223 Rem case, when it comes to obtaining the lowest possible ES/SD. Obviously, accurate and precise charge weight delivery is important. I weigh powder to approximately +/- half a kernel. That is certainly more than is necessary, but I can, so I do. I use high quality brass and I anneal my brass every firing. I weight sort a Lot# of brass into "Light", "Medium", and "Heavy" wight groups, because internal volume is generally inversely proportional to case weight, and there can be a readily detectable difference in velocity for the same charge weight between the very heaviest and very lightest cases within a Lot#. In fact, depending on the weight/internal volume variance of the brass, I have measured velocity variance for a given charge weight between Heavy/Light weight sorts (i.e. ES) to be as much as 20-30 fps. I often weight sort bullets, although I have to admit that weighing bullets, even on paper (theoretically), is probably not the greatest use of my time. As noted above, I also point bullets to get the highest possible BC.
The bottom line is that you can get away with a LOT using a non-optimal .223 Rem load at 600 yd that will kill your score at 1000 yd. In F-Class, the lower BC bullets combined with the increased ES/SD mean you may not only lose points (right/left) to missed wind calls at a higher rate than the .308 Win shooters using 200+ gr bullets, you will likely also lose some points "out the corners" of the circular 10-ring due to the increased vertical, even though your wind calls on those shots were acceptable. So anything you can do to tighten up your ES/SD numbers will be of benefit. I mentioned a few things I do above. You might also consider trying a higher BC bullet, although that may be difficult if you have to load to mag length. I assume from the BC you mentioned above you're using the 75 ELDMs. Nonetheless, there are longer/heavier/higher BC options available, if there is any way to make them work in your chosen discipline. You might also think about turning necks. I have not found it necessary to do so, but I know a few .223 Rem F-TR shooters that found it necessary to turn necks to get their ES/SD values down to acceptable levels. Another approach worth considering is to try a couple different primers. Sometimes that is all that is necessary to lower ES/SD. You did not mention the brand of brass you're using, but some brands are better than others. The Lapua name speaks for itself, but Lapua .223 Rem brass is pretty pricey. I have also had very good results with Norma .223 Rem brass, which is a lot less expensive. The Norma brass requires a bit more attention initially (i.e. uniforming flash holes), but the precision has been every bit as good as Lapua in my hands. Finally, I would strongly suggest you work annealing into your brass prep regimen sooner, rather than later. You can probably find lots of debate in online shooting forums over whether annealing brass really helps lower ES/SD. What I can tell you is that it certainly doesn't make the ES/SD values increase, so in your scenario it's probably better to get started annealing every firing sooner, rather than later. Many of these suggestions can be tested individually to assess whether they might be worth adding to your reloading regimen. You certainly don't need to attempt multiple potential "improvements" all at the same time, although ultimately those things you try that help will all be incorporated into a given brass prep. Just keep at it, even though attempting to reduce ES/SD with the .223 Rem might be tedious and frustrating, the effort will be worth it in the long run.
