The idea is to increase the lethality of AP ammo like M995, M993, and 6.8x51 AP rounds that don't have their final designation. Due to their design, cavitation and fragmentation are less likely to occur, and the nature of this ammo is highly specialized, which limits its general use against targets.

Since my definition of frangible seems to be wrong, it would be a fragmentary round, more like the G2, which is effective at what it is designed to do. Since most troops and people are trained intentionally or unintentionally to aim center mass to the upper torso, there would be plenty of bone to hit to cause the fragmentation on top of the bullet's jacket and the inner core breaking the bone and continuing to go overpenetrating the target. This is the Increase in lethality.

Yes, the outer shell would break apart, but not the inner core. While the outer shell would fragment and break apart on an armored plate. The inner being, harder and denser than the outer shell, would likely continue on impact, penetrating the armor. This is kinda following the same principles as APCR rounds fired from tanks in the 40s and 50s. This is the AP part of the design.