Well, in freedom units it is a bald eagle, and an NFL football field.
I would imagine its wingspan per cheeseburger, and when counting the small lengths we need to convert to bullets (which ironically goes back to metric; 50mm, 35mm, 9mm etc.)

I would also assume we are talking about length because that is the main topic (or was, I should say), and we don't want to confuse with liquids or weight.