Not sure if the OP is still hanging around or not.... But oh well...
The 60grn Nosler Partition is my go-to bullet for all things bigger than a coyote with the 223/5.56. The Monometals like the Barnes are a good option too, although I prefer the slower expansion of the Partition. The idea is to drive relatively fast expansion for reliable kills, but also retain a lot of weight in the shank to provide deep penetration and pass through.