No idea about the firearm, but the hybrid SS, Aluminum, brass cartridge violates many metallurgic principles such as dissimilar metal corrosion. I am sure they have corrosion barriers, but in the field, salt spray,moisture, and galvanic action most certainly will limit shelf life. At best I feel the ammo will have to be stored in climate controlled facilities, short life span in the field, and have extreme throat erosion.
Secondly, with top end operating pressures insures barrel life will be very low….good for the manufacturers, but a lousy deal for the unit armorers and supply chain…..a repeat of excessive, expensive barrel changes as witnessed by our latest artillery failures.
Good luck to our troops, they are going to wish it had a bayonet.
Galvanic corrosion was my first thought.
The chamber pressure exceeds the yield strength of brass which is why it has a stainless steel base.
The stainless parts for initial production are individually machined. Hence the estimated 10X price increase over current military 5.56
In order to deal with ammunition cost, as well as barrel wear, they are creating a lower pressure all-brass case training ammunition.
Which has a different aiming point. So they have a switchable optic for the two ammunition types.
No problem getting that right under battlefield stress/s