An article full of hot air.
SAAMI publishes modern specifications for 9mm by 19mm Luger ammunition. Either a modern manufacturer follows these specifications and enters the market responsibly or they don't.
Gun manufacturers design firearms to handle SAAMI specification cartridges, then test them to ensure safe operation.
Guns developed prior to the SAAMI specifications also complied with diverse standards that differed from the SAAMI standards. Wartime Lugers did not comply with SAAMI standards because those standards didn't exist at the time. But this article is not about wartime Luger pistols.
Cartridges go by a variety of marketing names. The original name of the 9mm x 19mm cartridge was the "
9mm Parabellum". The article author doesn't even mention that name in his overview.
ALL 9mm Luger ammunition is tapered. It's in the specification.
It tapers from the 9.96mm diameter base to the 9.65mm mouth, which is where the cartridge headspaces.
Nato standard "STANAG 4090" is a 1982 standard issued separately by NATO for their service cartridge. This specification is for a +P variant of the standard 9mm x 19mm pistol round with the same dimensional specifications as the 9mm Parabellum round.
In the United States, the cartridge is also know by a US Military specification: 9mm NATO 124 MC M882 Specs:MIL-C-7050
It is focused on interchangeability and the NATO process is discussed here:
https://ndiastorage.blob.core.usgovc...Pellegrino.pdf
A good overview:
https://ammunitionstore.com/content/...Parabellum.pdf