I got taken by TSA to the 'back room' because the red wand residue trace thing came up red after being ran down my clothes. If you go to the range within a week of being patted down the sensors will pick up the gunpowder, lead, whatever on you or your clothes, and more particularly things you normally don't wash like belts, watch, wallet, shoes. Surprisingly - and I am no fan of the TSA - after I explained why I was probably setting off alarms, they treated me pretty well. I was expecting them to get out a rubber glove or some crazy bubblegum. I was the last search the guy was doing before retirement. Just remember before flying (especially if you pass on going into the radiation chamber like me) to take extra care about getting powder residue off yourself and your clothes.