Standard is to flip the box and buy either the brown packing paper from a dollar store or christmas/birthday wrap from a dollar store and turning it inside out (so the white is showing). This prevents the slightly "transparent" wrapping paper from showing a gun inside the package and the package either disappearing somewhere with someone or some "concerned soccer mom" who may work at any point in the CP system to flag your package.
Also note it is a federal offence to open mail that does not belong to you however at times if a package has not been claimed for x number of days (I believe it may be 90 days) I believe the people at the depot can open it or something to that effect.
If they ask what's inside the package just say they're model replicas for a hobby ("imply" it's a hobby like model trains or model gundams or something but don't outright lie to them) or just say toys.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE