if you are old enough now to remember there was a forgotten "10mm" auto in the 1980s, the 41 action express
very similar to the 40 S&W later with but with a rebated rim for working in 9mm Parabellum pistols

this case was necked down and make the 9 mm Action express again 10 years or more before the 357 Sig

http://www.municion.org/

I think only cartridge collectors knowing this rounds today

the new cartridge could be an interesting round for the ar 15 , loaded with 300 grains bullet it must work like the 50 Beowulf