In the little, tiny, backwater of Mpls/St. Paul you can't normally find 28 gauge ammunition. The usual suspects will have a box or two of something, but, you can usually count on one or both of them being on the order of 1oz loads of steel 4s or something else just as useless.
I ran out of 16 gauge ammunition in South Dakota one time. I was all done with that gun until I cleaned it when I got home.
Where, I had plenty of 16 gauge ammunition.
Oh well.

Best,
Ted