I'm looking for a more powerful SHTF/TEOTWAWKI semi auto rifle to compliment a Mini 14 in .223. I am thinking a .308 or a 7.62 not really sure which of those 2 would be better.. I am looking for a very cheap option 750 or less USD. I am not very familiar with my options so I would appreciate if anyone can tell me what I should be looking for. Reliability is the second main concern after price. What are my options???