Original artwork, not a still
The metric system did not really catch on in the States, unless you count the increasing popularity of the nine-millimeter bullet.
Behind the line
What it means
Our interpretation.
The joke contrasts resistance to metric measurement with the popularity of a bullet named by its metric size. The exception gives an ordinary observation about units a grim turn. Its humour depends on finding apparent acceptance of the system in a violent example.
Context reviewed
