I wanted to know if I was crazy so I asked ChatGPT. Excluding buckshot and non-toxic shot, somewhere between 2/3 and 3/4 of all shotshells sold are 7 1/2 or smaller. I think 1 in 3 to 1 in 4 shells is pretty uncommon. 4 and 6 are not common or widely used outside of hunting. They're entirely banned from clay target fields. That they can be purchased at Wal-Mart doesn't tell me anything. I can buy and load #4 shot at Sportsman's any day of the week. It's never sold out because nobody wants it. If you don't consider that uncommon, choose your own word to describe it. There is not a widespread use for large, lead birdshot other than hunting of upland game large enough to require it, which I do not do, because I am a shooter, not a hunter.