I have always had good results with Remington green box centerfire ammo. No matter if it was 243, 30-30, 30-06 or 7x57 the stuff always shot very well. I have to work to get 243 handloads to match the accuracy I get using factory ammo.
But like Jay said, good luck finding any 223 ammo.
Have you ever danced with the Devil in the pale moonlight?
A village in Kenya called. They want their idiot back.