Welcome, Snap.
What a challenging situation. She's your daughter, of course, you love her. It seems to me you are asking more about boundaries here.
Obviously waving a gun around at people while intoxicated is not ok, nor is it legal. She could have been arrested for that - it is at least an assault offense.
But if she claims to have no memory of it - there is nothing you can do other than be firm with your boundaries. A good place to start might be to tell her she can't come around if she is obviously intoxicated. If she gets obviously intoxicated in your home, she'll have to leave. And then I'd hide the weapons.
Keep reading and keep coming back!
~T