Sorry to ruin all of your stories, but my friends and i tested some Rock Salt Shotgun Shell tests this weekend after watching "Kill Bill Vol. 2". We researched online and used a lot of your stories as proof enough that it was worth trying. Our results were less than impressive.
We filled .410, .12, and .20 gauge shotgun shells with ice cream rock salt as well as the more heartier rock salt made to melt snow off driveways. We obtained two pigs from my friend's family butcher shop and hung them from trees. As pig bodies are almost identical in terms of skin density to humans these were ideal for our experiment.
From 30 yards both rock salts with all gauges did nothing, we actually saw the rock salt bounce off leaves on the lower branches of the tree a few feet behind the pig.
From 20 yards there again was no damage at all to the pig. No skin breaking, nothing at all. This, as with all the tests, were with all gauges and salts.
From 10 yards there was some scrapes but no salt in the pig, except for two grains of the road salt just beneath the skin of the pig. When i wiped the pig with my hand softly both pieces easily fell out.
From 5 yards a few pieces of the road salt penetrated the pig skin. This was the only shot that would cause the desired "burning" affect. With the ice cream salt there was also just a couple of grains in the skin. My buddy who shot the pig was actually hit softly with ricochet salt.
I think if the pig had been wearing even crappy jeans like they sell in designer stores the salt would barely, maybe, penetrate the denim from even 5 yards away. I believe the only way to actually burn someone with shotgun rock salt is to shoot them point blank.
No doubt however if someone fired even a blank round at me I'd be scared as hell and run fast enough to place pretty well at the NFL combine. However, the truth of the matter is that there just wasn't enough mass in the salt to cause any damage at all. Maybe bruising from very close distances.
I'm sure people have filled shells with rock salt, but the stories of the "victims" of rock salt shooting have most definitely been augmented over time as the story was told and re-told.
After the test i cleaned my beloved .410 thoroughly while roasting the pigs.
