My most favorite rifle of all time was a Win. Mod. 70 "Varminter", with a 26" barrel in .223. The most attractive thing about .223 is free brass. If you can't find it, you ain't looking.
This one had a 12" twist, so I settled on the Nosler 50 gr. ballistic tip with 28 gr. of W748. That chrono'd @ 3,500 fps. It was topped with a Burris 6~24 Signature. There is nothing more to want in a p-dog bolt gun. My longest confirmed p-dog kill with that rig was just over 700 yards.