AR-15s are cheaper now than they've ever been. Ever. If you think you need a gun to keep around to hand off to a buddy in an emergency, I can't think of a better option than a bargain-bin AR-15 with an el-cheapo red dot on it. Easy to train, easy to use, and you can share mags.
Certainly better than handing out Mauser 98s and 6ft long shotguns.