Give Your Girlfriend A Box Of Bullets Day!
Tell her, "These are for your handgun."
She'll say, "Baby, you know I don't have a handgun."
Say, "That's where you're wrong." Then give her the handgun you bought for her from that guy. She'll be so happy.
"Oh my God where on earth did you get the money for this?"
Tell her that you got the gun at a discount because it was used for something pretty bad. But that it's clean. No traceable serial numbers.
"The owner just wanted to get rid of it because he knew the police would trace his crimes back to him one day, and he would be made to pay. When that day comes, he doesn't want the weapon in his house. He wants there to be no physical evidence. He wants to be convicted based only on the accusation and his confession."
Your girlfriend will already have started shooting stuff.
Be encouraging. Say to her, "Wow, that was a nice one," when she hits her intended targets.
I think this is going to be what makes her realize you are the greatest person on the face of the planet. I think this is going to be what makes her kiss you all over your face even on your open eyes.
Happy Give Your Girlfriend A Box Of Bullets Day!