I have looked at all the shotshells in the box, and have to afree that the marking should be FGC, but on about two thirds of them, the ‘G’ is poorly formed and appears to be a ‘Q’, as on those heads that are shown in the picture above. These letters were definately scratched into the molds, and it appears that only two molds were used to produce the shells in the box, as the markings on all of the shells match either one or the other set of marks, if that makes sense.
While studying the head markings, I figured out why all of those in the picture match. The other set of marks is much lighter, so when I was selecting a few to photograph, naturally I selected those with the prominent marks that would more readily show up in the picture, without realizing that the other marks were slightly different.
Thanks Chris for pointing out the references, and Shotmeister for sharing the information in #468, which I still can’t find. Sounds like the electronic version of the Journal may have been a wiser choice for me.