I've carried a full-sized one in an IWB, but didn't like it much-- I had to be careful not to bend forward, or the grip would become fairly obvious, and it made driving uncomfortable. I do frequently carry a Sig CCO (what they call a "C3") OWB in the winter when I can wear a vest or blazer indoors. In warmer weather, I sometimes carry a Sig Ultra Compact IWB (basically a Defender with a 3.3" barrel) under my usual Hawaiian shirt.