For SHTF purposes, there are 2 choices.

As Banan Clip says...12 GA in a short verson such as a Mossberg 500 or Remington 870...



Something like the AR or AK.




This is the Remington 700 5R MILSPEC in .308...my grail gun at the moment. That is, unless a 6 inch Python in brushed stainless pops up out of the weeds!