are they supposed to just have a billion guns in every shot or something?

Fucking. Yes.

I mean, not every shot, but the variety of firearms should absolutely be a big part of every action scene at least. It’s Borderlands, and that was it’s original claim to fame: countless combinations of procedurally generated guns.

Have your prop department whip them up as different parts that they can stick together, like how the games do it. Firing effects can be added in post.