Never actually tried it, but my WAG is that it would be mostly gimmick. The detonation sending the rock salt through the barrel would likely fracture the salt into smaller pieces. Than and the irregular surface wouls give extremely poor aerodynamic as well as ballistic performance. Very short effective range and little practical value, IMO. Having done rice in my BB Gun barrel as a kid, shooting at lizards and such, performance was crappy at best and inconsistent. If you are looking to be eco-friendly with rock salt over conventional shot, you aren't thinking about your defense capabilities very practically. Otherwise, rock salt would easily be defeated by most clothing anyway (lack of mass as well as the density of projectile material).

I am not a scientist nor did I sleep at a Holiday Inn Express last night. Just sayin' that it would make a lot of noise and the effective range seems a waste of effort compared to many other options in the SD/HD realm.

yeah i was just curious as i saw some rock salt shells as well as tacks and other stuff at a gun show booth a while back. having looked it up though i realize it was a dumb question, ill stick with 00 buck

Lots of anecdotal stories from before the turn of the 20th century had farmers shooting at apple-stealing kids with double-barrels full of rock salt. The results supposedly weren't particularly injurious, but salt inside a puncture wound would have been pretty uncomfortable.
I believe that most of these anecdotal stories aren't true, in part because shooting at kids, even apple stealing ones, would've been strongly frowned upon and stringently dealt with.
Further, its utility is questionable. As Growler wrote, "The detonation sending the rock salt through the barrel would likely fracture the salt into smaller pieces. [That] and the irregular surface [would] give extremely poor aerodynamic as well as ballistic performance. Very short effective range and little practical value, IMO."
IMHO, modern rock-salt rounds are gimmick souvenirs, more for show than for go. Nevertheless, loading rock salt into a plastic shot cup might make the round marginally useful against low-level offenders...if you could stand being arrested for over-reaction and physical endangerment.

no penetration...unless you are real close...you'd also need to clean the barrel really well since salt is a corrosive.

http://www.theboxotruth.com/docs/bot33.htm

only one way to find out.... I've got the 12 ga, Steve m1911 has the salt... who else wants to play?!

...Wait a bit...I'm having trouble reaching that last apple...

Originally Posted by Steve M1911A1

Lots of anecdotal stories from before the turn of the 20th century had farmers shooting at apple-stealing kids with double-barrels full of rock salt.

Wow, this brings me back to being 12.... Surely everyone had that crazy old man at the edge of the neighborhood who, according to rumor, shot at pestering kids with rock salt shotties?

Thanks for the memories, Steve

aww bruce you beat me to the box o truth

abit off topic of the op but, how reliable would you consider the box of truth tests? obviously you wont swear by them, and i dont think the military is going to change rounds because of these tests, but are they a decent indicator of round performance?