In 4, ever wondered why fire-based zombies are resistant against Cryo Grenades and their turret variant? It's because cryogenic things are extremely cold. In fact, it's so cold that it burns them!
The RIA Trident and HIKS M1000 appears to be too wide and too large (respectively) to fit in a Black Strongbox. This pretty much explains why they're only rewarded in Championships or crafted by hand.