You are correct. AF Security Police (not the Law Enforcement side of the house) were given 120 rounds for the M16. Overseas it was bumped to to 240 rounds. That is my SP experience (1973-1984), but it could have been different based upon where you were and what you were guarding. The most I’ve had to carry was 480 rounds during my stint in Thailand in 1975.
We also had access to and were trained on using the Mark 19 40mm, .50 cal, and 81mm mortar.
I was EOD so just observed, what an when we were drawing from your armory where we stored ours also.... ya’ll were air base defense heavy back then......What was it called.....SPEC’s Security Police Elements for Contingencies or something to that effect ??
NKP 73....Sawadi Cop !!