The primer is now a priming system that is enclosed in a brass casing. The brass casing is now the primer. The brass case used is unique. It has a 308 add diameter but the primer pocket is deeper for a magnum primer. The mouth has a chamfer for easier loading.
The brass can be reloaded/ re-primed approximately 4-5 times depending on the loads used. When a lot of residue is on the case head, you know that it should be replaced.