This really depends on what your expecting to be in a SHTF situation. A soldier or a survivor? If your looking to be a soldier i'd be looking at the 5.56 AR, FAL, Garand, AK, or M14. I couldn't go with an 7.62 AR, I'm sorry and someone might have a problem with this but they aren't as reliable as the rest. Sure great range guns but if your pouring down heavy metal that guy is gonna jam up fast. With pure reliability in mind you'd have to go with an AK. I choose the M-14 it's the best of both worlds. It is a great combat weapon, very reliable, and fairly simple in design. It also would be a decent survival weapon as the 7.62x51 can bring down nearly anything in north america, four or two legged.