First off, your a great friend! Regs in any military base will require the weapon to be registered and placed in the weapons vault. Coordination will need to be made to draw/turn in the weapon. BIG PAIN.
My idea: give him 25 bucks with the weapon and tell him to get a small storage unit just outside base. During my active days, I stored all my weapons and hunting supplies in a small storage unit and it was accesible any time. It costs about 25 bucks a month, but if your an outdoorsman, Its WELL worth it!!
Whak em, stack em, smack em
Good Luck and Be Safe!!