Ok here's what we do.
Drop Melvin into the Congo with nothing but his CAR, Star BM M-21A and with nothing on except a speedo and flipflops.
He can then forage for everything else he needs and prove us wrong.
Unless you are screwing up badly, you should not have to use your gun very much at all.
Shelter, food, medicine will all be far more important day in and day out than a gun ever will be if SHTF.
(or are you planning on spending most days in a year in fire fights?)
Even if you think you will need to play rambo and have one fire fight a week, you are still spending the majority of your time not shooting.
If you are smart, and reasonably careful, you may never need to fire a shot at another person the entire period that shtf lasts. (sorry if this busts your little fantasy about being rambo / mad max / whatever.)
Ever notice there are far more web sites on survival in the woods (I don't mean millitia or rambo or guntwit stuff). I'm talking how to find food, shelter, first aid, orentation, etc...
That should give guntwit a hint. If you can't find shelter or food or water then the gun means nothing. If you can't find you way around then your gun means nothing.
Every year handfulls of people survive being lost in wilderness, ships sinking (I'm sure that 11" POS CAR would be just 'vital' on a sinking shrimp boat), plane crashes, cars breaking down in the desert, or in winter, etc... but no, guntwit 'thinks' skills in these areas will just pop up in his head.