It sounds good and a logical improvement.

I still think that weight is inconsequential given that most roles are vehicular. Size of ammo is the real nut to crack.

I even wondered about squared rounds that come packaged in a cube

...you drop the cube into some kind of device that feeds each round to the gun.

And again, an APFSDS with .22 steel projos would in theory allow a round almost as small as 338 but theres the sabot danger.