Prime example, why imperial is terrible.
AWG 27 means 0.361 mm diameter. Imagine 7 strands of this. Kinda like a honeycomb, 6 will be around 1. Well not really, but it is easy to imagine. You have 3x the diameter, so it is 1.08mm diameter, between AWG17 and 18. The reason you can still crimp it is because it is easier to deform, and it is not 100% filled. The actual area of the cable is 0.1 mm2 for each strand, so something between AWG18 and 19.
Ah yeah, AWG the smaller, the bigger diameter. go figure.
Someone will explain it, that it is probably someone left foot multipied with a wallnut's area divided by 18, becuase that is a round number, multiplied by how far away a king in england could toss a rock.