I have a .223 with a 1/7 twist so I could shoot 600 yds with an 80 gr. SIERRA.
But I don't shoot competition any more.
Old eyes and iron sights are not a good combination.
For varmints I have a few heavy barrel bolt action dedicated prairie dog rifles.
I used to use 25-06 and .220 Swift but the 25-06 has been given a new life as a .270.
The .220 Swift gets used a lot less than the .223 rifles because the barrel heat in a prairie dog town is not ideal because of mirage.
So the .223 with light bullets does not require a quick twist barrel. 40 gr. V MAX or Ballistic Tips work equally well in a dog town.
So I would suggest you could get the .223 for prairie dogs but if you don't do that buy whatever floats your boat.
whelennut

I like to do my hunting BEFORE I pull the trigger!
There is only one kind of dead, but there are many different kinds of wounded.