I remember an ad for a company called Kaswer that made the "pin-grabber" designs in the late 80's or early 90's. The pin-grabber was an offshoot of Cirillo's design, which he designed for the stakeout teams he worked on. The idea was that fairly often, the only shot he had at a bad guy was at the head, and he wanted a design that was less likely to skip off. The teeth tended to bite into the bone and thin flesh and then penetrate past it. IIRC, Cirillo preferred auto pistols but to use those toothy slugs he was stuck with revolvers.
Now THERE'S a guy I'd like to have a beer with!
Papajohn