Physics...
I have a really bad shoulder so my journey with the 223/90 in F TR was a way to use tech to over come recoil pain. No recoil and I can shoot all day. Lower costs. When tuned properly, very good accuracy similar to any 308
Out to 600m, I am been on the podium at various western matches. Out to 1000yds, not so much.
Beyond 600yds, paper ballistics take a back seat to inertia. I bled numerous points on gusts that would push ALL of us. However, a heavy 308 would move within a ring or just out. I would be out 1 or more rings. This is not a misread of the main condition but a local system that comes and goes all over the range.
I shot with a couple of the top US shooters in Raton, NM this summer. They too got bounced around with their lighter 308 bullets. Me and my 90's, did surprisingly well all things considered BUT when a Raton gust hit, I lost at least 1 point for sure.
At this level of comp, you can't loose enough points to win.
For this season, I am moving to a 308 heavy set up to compete out to 1000yds. I will still use my 223 for practise cause it really keeps you on your toes to wind twitches... nothing better in my opinion. If I competed only to 600m, I would not feel disadvantaged with a 223 at all.
If you need any help setting up that 223, I have been there and done it all.
Here is video of my Savage/Shilen/MPOD FTR rig at 300m after coming back from Raton. Yes, things were pretty well dialed in. The 2nd shot was a slight wind rise I missed. The 4th was me aiming a bit low to ensure my vertical was still tight - the bullet went where I aimed. The center ring is the size of a tooney.
And what I used to shoot.
Jerry