They used to be the same. I was given a couple very large boxes of new hulls, from which the powder and shot had been salvaged at the Kent factory, and from which I salvaged the Cheddite primers. The hulls were all sliced up in a spiral fashion from the factory's salvaging operation, but I could see clearly that they were all Cheddites. I got thousands of primers from them. They were all 12 and 20 ga., being a mix of every different Kent hull I've ever seen. Almost all were damaged in some way during the loading operations.
I assume that the factory considered the powder and shot worthy of reclamation, but not the primers. I only worked on them when I had absolutely
NOTHING else to do.

SRH