Weird 30-30 brass

[Fatdaddy]

I'd go with it was reformed to a different caliber, and a conscientious reloader put the groove in there to warn that it was no longer the original headstamped caliber.

I sort of recall that there was a custom reloader who would normally do this when he converted cases.

Seems like a lot of work for such a common caliber

[quack1]

Most likely reformed from a different caliber brass, like others have said, but check the diameter of the flash hole. I made some mouse-fart loads in 30-06 and enlarged the flash hole to keep the cases from shortening and increasing headspace. To keep them from getting mixed with normal cases, I simply chucked them in the lathe and took a light cut to just remove the caliber stamp, leaving a raised ring around the outer edge and around the primer pocket. I can't be the only one to have done that.

[Noah Zark]

It's questions like this one that prove what a tremendous resource we lost when John Kort passed. He could have provided chapter and verse on those cases, with footnotes and references.

It was from John that I learned about those little copper rings that were once used to "lock" and "seal" a primer into the cartridge case head. We were chatting at the old "sight in range" (now "Cowboy Action range") at the Ridgway Rile Club during one of his and friend Jack's week long stays there. I asked John what kind of primers he had loaded those 30WCF cases with, and he explained all about the copper primer rings, and he used them to be authentic. RIP, John. I sure miss you.

Anyhow, if one were to do a search on John Kort's writings under his name, or his screen name "30WCF", you might find the answer regarding the cases in the OP.

Noah

[Doughty]

Most likely reformed from a different caliber brass, like others have said, but check the diameter of the flash hole. I made some mouse-fart loads in 30-06 and enlarged the flash hole to keep the cases from shortening and increasing headspace. To keep them from getting mixed with normal cases, I simply chucked them in the lathe and took a light cut to just remove the caliber stamp, leaving a raised ring around the outer edge and around the primer pocket. I can't be the only one to have done that.

Same here, but with .308 Win.