I overlooked a later article by John Atkins in the July 2018 issue of Airgunner, in which he discusses this very aspect about the flat heads on Bully bullets. Actual examples of the Bully pellets are illustrated and the heads are not as flat as drawn in the 1906 advert, although they are much flatter than most pellets. In actual tests, the Bully pellets performed well as wad cutters. A fascinating read!