Since you want a rifle to be dual purpose of hunting and a viable SHTF firearm, the .308 is a pretty good starting point. I like the A10, although I don’t own one; however, you’ll probably get funny looks while hunting if that’s a concern. I opted for a M1A that was originally an 18” Bush model and I added a scout scope for hunting (allows me to use stripper clips). It’s a little on the heavy side, but I’ve done enough hunting on foot that I’m pretty comfortable with the weight…plus a good sling makes a big difference. Other options are the Garand in .30-06, yet that too is a little heavy, but typical for a semi-auto military-styled rifle. If a mil-style semi-auto is too much, you can get really light weight and compact bolt guns (Savage, Ruger, Remington, etc.), however, they aren’t designed for extended shooting and high-rates of fire…unless you opt for a bull-barrel, but then the weights will equal or exceed a semi-auto. There’s a reason for military-styled rifles, and it’s their ergonomics, reliability and ability to sustain a higher rate of fire than your typical bolt, pump or lever action rifles. I love my Savage 110FCM Scout in .308; it is fast on target, light-weight, great trigger, excellent iron sights (although I have a Burris Scout Scope on it) and with removable magazines, pretty quick to reload. My only concern would be sustained firing (I wouldn’t want a sustained firefight needing 50+ rounds!).
If your hunting ranges are less than 150 yards or so, don’t discount the inexpensive lever-guns. Used Winchester 94’s and Marlins are common and easy to acquire inexpensively. The .30-30 is a very viable hunting and defensive caliber at realistic ranges…a tube fed rifle is easy to top off and on-board capacity is respectable most conceivable situations outside of being assaulted by a squad of Infantry. Adding a set of ghost ring sights will significantly improve target acquisition and speed.
I just picked up a Mossberg 500 12ga combo with an 18.5” cylinder bore barrel and a 28” accu-choke barrel. Another good option for those that can hunt bigger game at ranges 50-75 yards (slugs) and fowl with the longer 28” barrel…the bonus with the shorter cylinder barrel is to serve as a very viable self defensive gun with buck and slugs for most realistic ranges.
As mentioned, don’t forget a reliable pistol. Either a quality semi-auto or revolver would be at the top of the list. Most of your post-SHTF duties will involve repairs, work around the house, possibly picking up supplies, helping neighbors, etc. Having a pistol gives you a firearm on your person that can be very discreet, yet always accessible. Even in the military, duties of putting up tents/camo, filling sand bags, digging fighting positions, etc. we always stacked our rifles to work…of course we always had somebody on security, however as a civilian, you’ll have to pull double duty and a pistol is something to have on you 24/7 and allow you to get to your rifle if the situation requires it.
If I need a dual-purpose deer+game hunting rifle that can serve as a viable self-defensive rifle...here's my pick:
ROCK6