I have a few cheap plastic ammo boxes from Harbor Freight, and they've been great. If heat is an issue, it'd be easy enough to cut a hole and stick a mesh grate on it, but I have a PS similar to the one you mentioned and it's been fine without one.

Amazon link to a similar box: https://www.amazon.com/Plano-Cal-Field-Box-Black/dp/B07RC83LTZ/ref=sr_1_2?keywords=ammunition+storage+boxes&qid=1658593287&s=sporting-goods&sr=1-2