I think .22lr ammo is of little use other than plinking at this point. If it really goes to hell, .223,9mm, .40 is all going to be worth more by far.
For getting food I'll use my bow, and won't have a parade of people coming to see what's going on. In fact it would be a quiet defense as well.
A quiet 22 and a brick of ammo will let you all of the above should you find need for it. GW