truck gun
Nothing in the wifes sedan, but my pick up or Bronco will have a long gun almost always. Typically it will be in a soft case, either behind the seat, or it can tuck nicely beneath the rear seat of the SUV.
For quite awhile, I kept a Marlin '94/.357 and a ctg belt that way. Take it out, wipe it down, run a pull thru in the bore now and again.
For a while I went commando, and kept a beater AK and 4 mags. Figured the fall out from that in an incident would be monumental....so I went back to something more sedate.
As a fan of the "scout rifle", I currently go with a Savage Scout .308, , with a simple elastic ammo cuff on the rifle. A cheap cartridge box, the kind with a flap that holds the factory box liner, keeps twenty more rounds. I run a piece of paracord thru the keepers and suspend that off the headrest, behind the seat, if things were really ugly, I could pull that off and slip it around my neck.
The great evil has not happened, but I feel OK if it does. In the meantime, coyotes, feral's, fence posts, ....had better watch out.
The short Mossberg MVP would be another good candidate as a truck rifle.