The target in common use is the Figure 14. This measures 11 inches high by 7 inches wide and is often referred to as a Huns Head - in reference the original purpose of the competition, which was to train WW1 Snipers to kill Germans
The castle windows are only just wider than the target... Typically engaged at 200 & 300 yards but often extending up to 600yards for snap shooting competitions
I'd love to give this a try sometime and have seen video of the rimfire version. It's probably my Sporting Clays background, but I'd love to see more moving and limited exposure (limited time) targets in precision rifle competitions.
Just for open disclosure, I didn't compete there in the McQueens Competition. I was there for the Trafalgar Meeting, so it was more for fun and camaraderie than anything else. Still, some very fond memories. (I don't think I've ever seen that many Enfields, in one location, in my entire life.)