I have also had this question pop up many, many times. It is usually one of the first questions that pop up when people find out I carry a concealed weapon. My answer though, usually comes in the form of a larger discussion. The results of which lead me to a different conclusion and recommendation. To be clear, I have shot the KSG and it is AMAZING. So I don't want to take anything away from the recommendation or legitimacy of the advice for owning one.
For the discussion though, I think it's important to start with a solid acknowledgment of risk. There is a very high likelihood that you will find a use for a home defense weapon at some point in your life. In 1985, the Bureau of Justice Statistics made a report on the likelihood of victimization (
HERE). The report shows a 72% chance that you will be the victim of burglary at some point in your life. That is, of course a very broad statement, but even in rural areas it is 64%.
That's only the starting point of the discussion though. If you acknowledge the risk and want to take steps in preparation to prevent being a victim, there are quite a few steps that are practically better and more effective. It is much more effective to avoid the situation. Motion detector lights, alarm systems, camera systems, large signs, etc., make huge steps towards preventing the invasion from happening entirely. At the very least, you will be reducing that 72% down to almost nothing.
If you still want more though and make plans to protect yourself in a home invasion, there is one big question that you need to seriously ask yourself. Do you have it in you? I don't mean this in a challenging way, but as an honest question that you have to ask for yourself. Do you have the almost sociopathic ability to end a life without waiting too long or with full knowledge that you might be going too fast too soon and end up with charges? It is human nature to hesitate before making a decision that is so.. final. You might find that after an honest bit of introspection, choosing a "less than lethal" option may be a better option for you. I have experienced both the taser and the pepper spray (for work), I assure you they both are quite effective against an average person. Either way, using a less effective solution in time is far better than having a more effective solution that you failed to use in time.
So if you are still looking for something a bit more definitive and still want a firearm, my recommendation would be for a pistol. The main reason for it is, once again, likelihood. If you're this far "down the rabbit hole", and still want to be prepared, you have to acknowledge other risks. For instance, you're 10% more likely to be a victim of a violent crime than a burglary (83% instead of 72%). So you might want to consider concealed carry. If you do, you can't really conceal a shotgun.
So following that path will then lead you to the question that started this long winded reply, which caliber. I would first recommend reading this article (
HERE). I think it puts things into perspective. One thing's for sure. There is an absolute ton of information out there and it is a highly debated subject. Some rounds have a better chance of stopping and some have less. However, some are much more difficult to shoot than others. I believe in a balance. I believe you want a pistol that is comfortable for you to shoot, even if it's a .22.
The reason I place such a high premium on comfort, is because I place an extremely high importance on actually being able to safely and reliably use the pistol. You absolutely need to hit what you're aiming at. If you can't, you're arguably just as much of a risk than the person you are trying to stop. That's why it's important to practice, practice, practice. You practice till your hand (not just your brain) knows where to shoot. You practice till you can hit the target every time and never miss. You practice till you find yourself indexing your Black and Decker drill at home. You won't do that if you have chosen too large of a caliber for your specific level of comfort.
The article I linked makes for some very strong support in favor of accuracy vs stopping power. In fact, it changed my mind from looking solely at raw stopping power, to looking at accuracy and usability as the main points. It just makes sense to me. Even the most effective calibers won't work if you can't hit, be fast enough, or it's just uncomfortable enough to convince you to skip range day. That's why I would recommend trying out as many calibers as you can before making a decision. Find one that works for you and get wicked good with it. Because at the end of the day, the best caliber to carry for self defense, is the one you have with you when you need it.
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