Was looking at the Vortex AR-BDC3 reticle subtensions and noticed the hash marks for 300, 400, 500, and 600 yard holdovers were progressively narrower. Lo and behold, the subtensions all correspond to 8.8 inches wide at those ranges. What target or ranging reference width is 8.8 inches? That's almost half the width of an IPSC silhouette (18"), but it isn't exactly, and it's about half width, not full width, so it wouldn't be very useful as a quick ranging verification.