25 grains of AA2015 50 grain Bal Tip Shoots extremely well in everything I have tried it in.

My experience is a 1:12 twist should easily stabilize up to a 55-60 gr bullet. At least at our atmospheric in MO/KS.

I forgot to add my barrel is a 1:8 twist. I sincerely appreciate everyone's suggestions. I realize a 223 isn't a "barrel burner" but one other concern I have is Im at least the third owner of this rifle. Honestly I hit what I shoot at in a hunting situation, and maybe I should be content with that, but trying to work up a good load has been frustrating to say the least. Looking to possibly rebarrel. Down the rabbit hole I go.

An 8 twist is for shooting heavy for caliber bullets in a 223.

Try some 65/70/80gr type .224 bullets.

Make sure your barrel is clean. Use a good carbon and copper cleaner. Most people think the barrel is clean, but it isn't.

This^^ I had some 45 gr .224 bullets taht said dont use then in anything faster than a 1 in 9. The spin any faster was to much for them..
Try heavier bullets or solid copper since thaybare longer being lighter than lead. .
And copper fouling is a thing like said above. A ammonia copper cleaner and nylon brush then patches to dry. Repeat until patches come out without the green tint from the copper.