ForeruNner 5,7 x 28 P90?

Hi everyone. Once again I need help and opinions from forum members to identify this cartridge.
Recently, I have bought some predecessor cartridges of the 5.7 x 28 P90. But I have some doubts about this cartridge, since I cannot find references to it anywhere. During my life as a collector, I have seen many of these cartridges with different lengths of case, bullets, short and long neck … etc). I can only show measurements of the cartridge, and say that it has been purchased from a world-renowned collector.
Measures:
Bullet diameter: 5.64mm (0.222)
Diameter Neck: 6.44mm (0.253)
Length of caseimg353


: 23.41mm (0.291)
Diam. Rim: 7.71mm (0.303).
Bullet magnetic.
One last comment: YES, everyone can see certain “strange” marks on the shoulder of the case … but I have no idea.
Thanks to anyone who can contribute ideas or comments on the matter.

The “shoulders” of the case look as if it was equipped 2 times, at least. The bullet is similar to the M193

5.7x24mm rounds mentioned here:

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