This is just another silly 'what if' Hollywood type situation unless you open the discussion beyond guns. I reload for every center fire I own, so I have reasonable stockpiles of components for all. Practice would stop in a SHTF scenario and it's doubtful that all that many bad guys are coming my way in particular-that stockpile will last quite some time.
What will be in short supply post Armageddon is readily convertible sources of energy--i.e. gasoline, natural gas.
Transportation will fail almost as fast as the lights go out and the water stops flowing. Bicycle is a mid term option, but replacement parts will dry-up soon. There will be no planes, trains or even trucks in very short order. Time to find a horse or donkey or ox-if they survived.
Hand tools and seeds are essential to establishing a balanced sustainable food source--fresh meat is nice, but what makes anyone believe that animals will survive a disaster that rips civility apart? Know anything about salting meat, drying, dehydrating or smoking? Better get those skills before you knock down a surviving deer or elk unless you want most of the kill spoiled.
Medical supplies and sanitation is next. Can you get by without allergy meds? Or BP pills? And even if all the dead somehow dissolve without the associated disease, what about all the waste from those that survive?
At his point maintaining a home and finding clothing will go from just expensive to critical and time consuming.
So, can you farm or perform some cottage type industry like weaving or grain grinding or blacksmithing. Smart and sturdy enough to herd livestock-assuming some survives-hell do you have any skills that you could barter for food, shelter, clothing or medical care? What will pass for money?
Unless you have a relatively minor catastrophe like a hurricane, typhoon, tornado, flood, wildfire, mudslide, earthquake or volcano on the small order that earth/humans have already survived--most simply by being far away, in a true complete breakdown of society via some holocaust, which gun to have will be secondary to just staying alive.
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