Handguns are particularly good when firing in proximity to friendlies. As are blackpowder weapons, particularly precussion revolvers. Lot less barrier penetration, and a lot more surface area to badguy contact and resultant energy transfer. Also blackpowder and ammo is extremely easy to make at home compared to high power weaponry. Black powder is an exceptional backup option, and I think should be kept as an auxillary to a modern arsenal. When using pyrodex as much as possible, the smoke factor is also much more tolerable, and indoor defensive fire can be used without chocking on your weapon's fumes and setting off the smoke alarm.
Also, bayonets can be affixed to black powder weapons, which makes you infinitely more deadly than even a main battle tank
To round our your arsenal, a good selection of bladed weapons should be kept too. They can be quite useful for quiet disposal of intruders when you must take them out without alerting their buddies. Crossbows are also useful in this role, though not as effective against body armor as axes and broadswords.
Basically if you can get two weapons for each likely need, then you will be well off if there is a social collapse. Assuming there is no social collapse, it's really a matter of getting whatever you want really. Still, there is always a bit of social dischord, so at least one purely self defense weapon is a logical addition to your recreational picks.
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I twist the facts until they tell the truth. -Some intellectual sadist
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