Chris,
There have also occasionally been MAJOR changes in long-time standard primers over the years, often without the manufacturer announcing any change. A good example is the CCI 450 magnum small-rifle primer. When it first appeared. the only difference was a heavier cup, to withstand pressures over 50,000 PSI or so. Sometime later the amount of the priming compound was increased, and in the 1990s the compound was changed to a hotter formula--and the CCI 250 large-rifle magnum's compound was also switched to the hotter mix at the same time.
