Most any modern, repeating firearm will be adequate for running off the opportunistic pissbags who loot following a disaster. Pillagers are a bit different. In addition to your material goods, they may be planning on enjoying you. Since I have a little girl to protect, pillagers will be killed w/o benefit of any warning shots or other foolishness. I have a Bushmaster carbine w/ a 16" fluted barrel that would work beautifully for the purpose, especially with a 30 round magazine. The red dot sight I have mounted on the carry-handle makes it that much quicker to use against multiple opponents.
Depending on the situation, I might opt instead to use my PTR-91. It is a domestically produced version of the HK-91 that fires the 7.62x51mm cartridge. It is sufficiently penetrative that said pillagers would be able to find very little in the way of effective cover anywhere around my place.
Scumpup, drop me an email if you could. morgrandall@yahoo.com I’ve been considering a PTR-91 but have a few questions.