These .30-caliber (7.62 mm) full metal jacket bullets show the typical jacket openings exposing the lead alloy core on the base of the bullet to illustrate that a full metal jacket may not completely enclose the core.
Examples of FMJ bullets in their usual shapes: pointed ("spitzer") loaded in the 7.62×39mm rifle and round-nosed loaded in the 7.62×25mm pistol cartridges