I have an American 223 Lightweight that shoots 1/2" groups all day with 24.0 gr. of Varget & 70 gr Noslers. Only problem is that the magazine well isn't long enough for the longer 70 gr. bullets. I emailed Ruger to see if they offer a longer magazine and their reply was to NOT use handloaded ammo. Not the answer that I was looking for.
I shoot some Speer 70 grain bullets loaded at or little longer than book listed COAL and they shoot very well.. you can shoot longer bullets and load them to my length and start there you might be surprised how well they can shoot even further off the lands.
Just use caution when you're getting shorter than listed COAL you'll be taking up case capacity and raising pressures just keep that in mind.
