RE: "in" caliber
I think the answers are determined by how the question is phrased. "IN" could mean the great 30-06, which (I have read) leads in ammo sales and reloding die sales for centerfire rifles. "IN" could also be meant to address the most purchased centerfire caliber for big game in the last calender year, and this could be the 300WSM, or some other "currently popular" caliber. As we learned from Bill Clinton, "it depends on what the meaning of IS is!"