In my native language, we sometimes use the expression "to be shot by (Someone)'s eyes", meaning that Someone is staring at you very intently and in an examining, measuring manner, most often trying to find out whether you are lying or not.
While writing my fantasy novel, I used the expression without giving it much thought, but it keeps bugging me, because gunpowder has not been invented/discovered in my setting.
In my specific case the expression is used by a third-person limited narrator, but I'll make the question more generic.
Is it ok to use a metaphor none of the characters would understand because of tech-limitations? (or any other limitation, for that matter)