The guns are deadly, the shotgun is supposed to be firing rubber though. Despite how she is portrayed, she doesn't actually find the idea of killing people exciting.
Depending on what kind of bullets used. Something like rubber bullets used by police officers in a civilian riot, salt rock can be used for shotgun to make non-lethal punch. Even so, it's still dangerous and become lethal. So, please, don't try this at home
I wonder how long that phrase "I've cut another useless thing" will remain in manga memory. Will we continue to see it decades down the line like dragon ball and laputa references?
A lightly-loaded shotshell with say, cotton wads or some other semi-soft projectile, could be considered less-lethal, but still not something you want to hit you. You don't need quite as much powder in the shell to launch something that isn't a handful of lead.