Devnull: One of my favorite bullets for Hunting Prairie Dogs with my 223's is the wonderful 50 grain Sierra Blitz (not Blitz-Kings!).
I have used this bullet in MANY 223's during the past 30+ years and not only are these bullets accurate they are amazingly lethal on Prairie Dogs out to a ways past 400 yards!
And they are affordable and consistent year to year (decade to decade!).
Several of my 223's prefer this Sierra 50 grain Blitz bullet (#1340) along with H 4895 powder and Federal 205 M (Match) primers.
Be sure and give these bullets a try.
Best of luck to you with whichever you choose.
Hold into the wind
VarmintGuy