So what does the BATF have to say about it. Is a .54 cal miniball paper cartridge available in normal commercial channels, or a .380 long, .32 rimfire or .38-50 Ballard Everlasting? Are there guidelines, or rules or publications regarding this?

I was referring to the U.S. although I have seen this phrase in UK and Australia.

What is this. All ammo seems to be available one way or another. Obsolete just meens the big manufacturers don't make it. Is there a list of calibers.