Ctac IWB, no undershirt or underwear, first little bit of sweat glues the holster to your side
For 20 years I used a Milt Sparks IWB but retired it 4 or 5 years ago & switched to a Comp-Tac CTAC also, although I find it more comfortable either pulling underwear up between it & my skin in warmer conditions or tucking a shirt behind it when I use a covering garment in colder ones.
I prefer it to the MTAC/ Crossbreed style because the leather gets sweaty when on the range all day outside in hot, humid weather.
I wear mine daily year-round... I mean everyday doing every activity except swimming. Even teach quite a few classes using it.
The all kydex construction works well for me when teaching, mowing, weedeating, working at the range or around the house.
