I went to the local Ace store today and bought a box of wood screws,
size 10, Hillman brand. When I brought them home I decided to check the
shank size, and was surprised when they came in a little small, about
0.150", instead of the 0.190 that I was expecting.

https://i.imgur.com/xlke7UK.jpg

Thinking I might be losing my mind, I measured an old wood screw that I
had laying around, which my mind told me was a #10, and it measured
0.190". I even called the local fastener store, and they confirmed that
0.190" (or 3/16 as they put it) is the proper shank size for a #10 wood
screw.

So what's the deal now, did I end up with a mislabeled box of wood
screws, or did someone change the specs on these things while I wasn't
looking?

Jon -- puzzled