http://en.wikipedia.org/wiki/ShotgunRock salt shells are hand loaded with rock salt, replacing the standard lead or steel shot. Rock salt shells could be seen as the forerunners of modern less-lethal rounds. In the United States, rock salt shells were and are sometimes used by rural civilians to defend their property. The brittle salt was unlikely to cause serious injury at long ranges, but would cause painful stinging injuries and served as a warning. Some Spanish police forces, like the Guardia Civil and Cuerpo Nacional de Policía, use special rock salt shells called SAL-90 in their riot control units.
OK, so that is what Wikipedia says. It should be noted that there is [citation need] after that paragraph. So, we are told there are commercially produced rounds call SAL-90. Piece of cake, right? A simple search should show the maker and shells. After all there are enough collectors around, these should be sought after. So, some one please show us one of these commercial loads....
The 1st Shotgun entry - Mar 27, 2001
http://en.wikipedia.org/w/index.php?title=Shotgun&oldid=280239Salt added to specialty ammunition section - Dec 29, 2005
http://en.wikipedia.org/w/index.php?title=Shotgun&oldid=33063357SAL-90 listed in the Wiki - Aug 28, 2008
http://en.wikipedia.org/w/index.php?title=Shotgun&oldid=234871383I used to hear the stories as a kid as well. I have never known anyone who used rock salt in a shotgun.
Pete