In terms of simple pragmatics, it bears pondering that unless one is part of a large and well-armed force, shooting at anything that can shoot back (especially a group of anythings that can shoot back) is a risky proposition of the highest order. Armed with anything from a Ruger #1 to an NFA-registered AR, if you're around and in sight when the other group of individuals realize that you're there, the John Woo style gunfighting tool is simply a means to affect how many of them you can take with you. If that is the goal, go-booms are far more effective than any go-bang and much more inexpensive to fabricate and maintain. The rifle is very much an offensive weapon. If any sort of SHTF scenario discussed here (or elsewhere) were to actually take place, the role (with particular focus on its abilities and shortcomings) of an offensive weapon should be examined very closely if you're not going to be part of a large and well-armed force. Things that an entry team or military unit can do (e.g., suppressive fire) may be flat-out unsafe for an individual. One would be better served (though perhaps still not well-served) by observing the habits of one and two man units as opposed to the habits of divisions and platoons.
I've lost count of how many times I've bested a superior number of cardboard foes in IPSC and IDPA. I've also lost count of how many times I've bested a superior number of real foes with a fake sword. I recall vividly, however, the first time I did not succeed in doing so. I remember thinking "Well, so, I gues I'm dead" the first time I "died" in a field melee. I was stabbed in the back. The second time I died, I was shot in the back with an arrow. The third time I died was on the end of a better swordsman's weapon. As some say, "they can miss all day, you can only miss once." The weapons have changed, the tactics have even changed (though not as much as some would think), but the reality as it exists to the individual has very much stayed the same. Engagements against a foe of superior numbers cannot be won without some major force multipliers. An AR/AK/FAL/etc does not count. A gun emplacement or go-boom does. Luck/Fortune/Chance are also valid in this regard, but are too fickle for my taste.
The advantageous nature of the semi-automatic rifle is quite diminished in the hands of an individual. Riot control? Worked in LA, but only because the shopkeepers in question had the high-ground. From a rooftop, having enough bullets is a concern. Being able to fire them as quickly as one can wiggle their trigger finger isn't. Had those looters been armed with rifles instead of rocks and other blunt instruments, I assert that the outcome would have been much different.
Attacking a larger, well-armed group with a rifle of any kind, be it a single-shot or fully-automatic, is tantamount to suicide. The automatic will increase the number of them that you can take with you, but one, five or fifty doesn't change the outcome. You died. Luck can pull you though, but don't count on it..
That said, my rifle of choice would very much be semi-automatic. Not because it's a semi-auto, but because it's what I'd deem "enough" rifle. It happens to be semi-automatic. That very same M1 Garand brought my uncle home. I hope it'd do the same for me.
) If it really hits the fan, you've gotta think aobut what can be fed for the next 20+ years...
