You cannot go by what the clueless media calls “heavily armed.” To them, a sharpened nail file is “heavily armed” if it sells papers.
I would call a rifle heavily armed, and a pistol lightly armed.
What would you call a sling-shot?
Only to use my Alabama wisdom here.....but evidently, they weren’t heavily-armed-enough, thus meeting their end and requiring more time to do the cop paperwork on the episode than the actual fire-time between said-party-A and said-party-B.