If you neck down a 357 Magnum case to .244, what is it called? Is there a version of a necked down 357 Maximum to .244?

This would be very close to the euro 5.6x50r.

.243/.256 Winchester Magnum

I had the computer neck down these 2 cartridges for comparison, The 243-256 has a case capacity of 21.26 grains H2O and the 243-357 has a 28.33 grain H2O capacity.

.243/.256 Winchester Magnum
edit-- ( missed the Maximum above)

Guess it should be
.243/.256 Winchester Maximum

Thank you for the info and drawings.

I believe the Maximum necked down would be the Rimmed version of the 6mm/222Rem - 6mm/222R or 6X43R
The .244 on the 357 Magnum could then be 6mm Winchester Rimmed Mag or 6mm/256 Winchester Mag or 6X33R !

6/357 would be my call if I built one..