30mm PGU-14A/B API (GAU-8 round)

I recently saw a picture of a sectioned 30mm PGU-14A/B API round for the GAU-8.

If I understand that picture (source: ATK) correctly, I see, on the front end of the projectile, a thin metal windscreen. There is a hollow space behind that. There is a metal “cup” (essentially the bulk of the outer projectile) that holds most of the DU penetrator.

How is the penetrator seated in the rest of the projectile? Is it glued in? Or pressed in? Once assembled, can it be removed or is the force of impact the only thing that dislodges it? How does the DU penetrator behave when the round strikes a target? Does it continue through armor while the rest of the round is sheared off?