Is hunting in Iowa legal with FMJ bullets?

I was coming close to the end of my shift at work and I was talking to a Co worker and I mentioned that I was going to pick up some FMJ bullets(.223 55 Grain) at the local Cabelas for hunting varmints. He said to me that its illegal to hunt with FMJ in Iowa. This doesn't sound correct, or at least I won't believe him until I get information proving otherwise. Could someone supply a link-or past experiences. I looked on the DNR website but that was a waste of time. To be honest I don't think someone would find out what you were shooting with anyway(I still follow the law though.)