The menace of .223 caliber three-rounds

We all know the typical journalist loses 50 IQ points when writing about guns, so you expect them to use made-up terms like "semi assualt rifle" and "high volume bullet clips."  But what could the South Bend Tribune's Jeff Parrott have possibly meant by:

In particular, the store has proposed selling .223-caliber three-rounds, which is used in high-powered rifles such as the A.R.-15, Dieter said.

Anyone?  Jeff? 

And how could the reporter omit the very relevant fact that the controversial .223 cartridge is far less powerful than the politically correct 30-06, which, presumably, the zoning board is not concerned about?