This should be interesting! It would appear they have protected against case head separation (cough PCA cough) however having a seam just under the shoulder seems a little iffy. It would be interesting to see a section of one of these.
How would a polymer case reduce flash? Same loading, same velocity, same projectile = same flash, no?
How would a polymer case carrying minimal heat out of the chamber reduce temperature within the chamber?
Maybe it reduces the flash of the shell casing flying through the air? You know, just in case you’re shooting a PSG-1 that self identifies as a grenade launcher?