Capitol Hill Blue Forums Political Issues Guns In production movie Rust

Saves money on post, much more convincing on impact.
But you're right if you're saying it's not always necessary.
Production wanted Mel to actually SHOOT the aquarium with a live round on Lethal Weapon 2 but Mel argued that he wasn't 100% sure he could hit it in exactly the right spot for maximum effect.
Yes, he said he knew he COULD HIT the aquarium alright, but he wasn't comfortable with having other talent so close.

So they used clever editing and a squibb (remote impact charge or detonator) to crack the glass instead.