1. The Army did not ban PMags. They issued a memorandum stating that only magazines on the "approved" list be used, then only put the USGI magazine on the list (tan and green follower versions). After an initial uproar by those deployed, the Army issued a clarification less than a week later saying the memorandum was "optional".
2. With the USMC, the introduction of the IAR (with it's extended 416 magazine well) did not allow the original PMag to fully seat. This caused an incompatibility with the existing PMags (all pre M3) already fielded by USMC units. The M3 has since solved this issue as well as HK who have move to a conventional mag well design with the latest 416 varient.

