Something like a taser isn't enough as to truly replace firearms it would need to be non-lethal and obviously somehow completely incapacitate at range. It's "cops and their guns" so ostensibly this might seem like an American problem but I'd imagine if you pulled it off it could be an enormous industry worldwide.

This just seems like a critical problem in need of a solution (which might require funding etc. but would have enormous potential)

The obvious impetus for the question is the latest senseless murder in South Carolina.