After watching that somewhat stupid remake of red dawn I was wondering just indeed what would be a “better” weapon than the AR15. If it was all that I could get I would use it but if I had a choice I would immediately use something else.
Probably what the enemy uses first, then if I could then I would get above using the .223 and go to a 6.8 at least.
As with the liberator (single shot) .45 pistol of WWII ,use what you have on hand until you can get something better
The Springfield Socom 16 M1A is not a bad choice in .308!The Tactical Mini 14 is also accurate as hell and a hoot to shoot in .223 or 5.56 Nato.
Today there is no better weapon for a US civilian contemplating a SHTF scenario than an AR-15. While the round may have limited lethality and range what you get with the AR-15 is interchangeability with the tens of millions of military 5.56 mm NATO ammo and M4 magazines. Any US soldier and most police can be a source of ammo and magazines to you.