I don't know if it's UCMJ or not, but you're only allowed to cary a knife with a 3 inch blade on base in the Army, however a Leathern or such is a tool, not a knife, if you follow.
Forget about fixed blades, you ain't carrying any sort of weapon on base unless you're an MP, I don't know if concealed carry permits will get you anywhere.
In the field it's different, though at the discretion of your commanding officer, or his.
Anyway, all weapons have to live in the armory, though they will number and catalog the weapon and you still have access to it for hunting or camping or when you leave, you just need to let you C.O. know. Anyway, they're accountable for your stuff, so they take real good care of it. Well, I'm sure there's exceptions to the rule, but they're pretty responsible about weapons.
I remember how in Boot they locked down, was it Kelly Hill?, because a M-9(the pistol) went missing from a display or something and didn't let anybody leave till they got it back, some days later.
Anyway, the only weapons you really get to play with in the service when you're not in the field is what they issue you and specificaly order you to use/carry/train with.