Guns? You’re worried that they know about guns? There’s a lot of information that is so inappropriate for frum kids to know, or have been exposed to. This is the least of the battles, now that we are well into the information age. Our children are not confined to cocoons, and there is more than enough that is challenging that is endemic to our homes and communities. One does not need a smartphone to know about a whole lot of stuff.
I find this question comical and primitive.
In reality, we cannot successfully shield our kids from everything without actually suffocating them. Our responsibility, once we have done our best to fulfill the mitzvah of והי’ מחניך קדוש, is to build our children’s cheshek to want the derech of Torah and Yir’as Shomayim. Sadly, this is not very popular. Even the מחנה stuff is not faring well either. But we are at least obsessed with it.