What req packs should I buy to unlock armor mods

Games Halo 5: Guardians
1

I need help trying to get armor mods I have opened up at least 20 of each req packs and haven’t received one armor mod

2

I’ve gotten five armor mods from Gold packs.
Also, this section is for introductions ONLY. Not questions.

3

I got one from a bronze - the only bronze I ever opened

4

What?! I HATE THIS! I have bought exclusively gold from lvl 1-30 and then only silvers and bronze from 30-50 and still no a single Armor Mod!!! What… How… I have no clue what I’m doing wrong.