Their math was flawed, but I’m not really sure how to explain the math part better. I get what they were going for, though.
It’s closer to decimal divisions of an inch, so a .223 caliber bullet would be a hair shy of a quarter of an inch (.25) wide.
Edit: just realized you had the second part of that already
Bro
I could not keep Good Friday and Black Friday straight until I was in my teens
But no, it makes perfect sense that the good sounding one is when a guy died, and the bad sounding one is a good time to do Christmas shopping… /s