I bought a small collection of bullets and a few molds over the year, and M&M's book, but basically know nothing about either. I'm not sure what chasing is, and not even sure of the age. trying to research, that style mold was listed rev to current ( repro). I don't think it started as a round ball though. it has that weird stepped base and then the sprue, the base would take ALOT of work to take off as its almost the size of the bullet. The teat could have come later with a "drill" of some type. the base and center ball area are well finished, the teat looks like it was done with a damaged tool and shows several small grooves which don't show as well in the picts. it looks "unfinished". So I looked at M&M again, eliminating the teat in my mind, and still didn't come up with anything. It does resemble several revolver bullets, but they were not that big. Maybe for a cartridge? some of those look similar but this still has more of a teardrop shap than the ones I saw