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There are a host of problems with this solution: you would need to make your own rock salt rounds, you would need to clean it pretty extensively after use, rock salt is all but useless for anything other than making a big noise, and… switching lethal and non-lethal rounds in a gun is asking for a mistake. You wake up because someone broke your window, how sure are you that you have rock salt and not buckshot?</p>
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A few of the same problems, but a better option at least, provided you can manhandle a 12 gauge in tight quarters. I would suggest dedicating a shotgun solely for non-lethal use, if you go this route.</p>
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It’s basically just pepper spray, and other than being more generally legal, I haven’t heard of any real improvement over standard pepper spray. I have been underwhelmed with pepper spray, and the big problems I have heard from cops is that (1) some guys, when sprayed, just start swinging blindly and that (2) to the extent that bad guys have weapons, they keep using them during this time. Pepper spray is great when you are in the open looking to escape (because it WILL slow them down!) and works just fine as part of an arsenal of options, but is otherwise a weak option.</p>
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A taser is again a decent option, but have distinct limitations - civilian models are only good to 15 feet and typically only have two shots with slow reloads (if any!). That can be a big limitation in a fight.</p>
<p>There is the contact-type, but, well, you have to be close enough to touch, and for a lot of people that is a point where you are already screwed.</p>
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Everything has been known to kill people. It is not possible to take an action against another person with zero chance of them dying.</p>
<p>It seems like the best non-firearm defense is in variety and practice - keep pepper/bear spray AND a taser of some type AND a baseball bat handy, and make sure you practice enough with them to be proficient. One thing I have read over and over again is that the more aggressive person in the fight has a HUGE edge, and that is usually going to be the criminal.</p>