This note does not contain major spoilers for the book.

Quick reread.

I seem to have somehow missed noticing, before, that it's named for the big heavy rubber band used to fake the gunshot (which I don't find too believable), as well as for the funny name given to the group and its leader "Rubber" Coleman. I think they said it was 3/4" across, so maybe it would make a very different sound than any rubber band I've ever encountered.