How often do massacre/slaughterers carry bombs on them? Of course the gun industry would riot because so many deaths are on their watch using what they manufacture and well they'd go wacko with no buyers.
Of course they could all convert to being BOMB makers. Probably more costly and you'd have to handle them very carefully. Guns can be kept in gun racks locked up. How do you lock up bombs? Word to the wise. Improvise. Convert. Guns are antiquated. Bombs are the future. Bombs away! KABOOM! Oh boy!