User blog comment:Kodachi-sama/HINT in the Ruby Trailer??/@comment-5043861-20130303231617

The 3:06 shot (the image pictured) is black. Compare them to the shots before she reloads (2:40+). Like Kodachi-sama said, it could be the magazine she reloads with. The image on it seems to be implosion (arrows pointing inward to the target/circle), while the white shots (blank?) are default or explosions.