[ButThreeLeftsDo]

You can't get BB shot in a .28 gauge shell.

Nor, buckshot, as had been widely reported.

[MineralMan]

"You can't get BB shot in a .28 gauge shell.
"

Not commercially. You could load them yourself, though. You could even do buckshot, although I can't imagine why you'd want to.

Commercial 28 gauge shot shells are limited pretty much to 7 1/2, 8, and 9 shot. The local Fleet Farm here only has 8.