Rocket launcher using pistol ammo


I can’t remember exactly how I did it, but I accidentally somehow loaded I think it was 9mm ammo into the rocket launcher. So I had like 900 rockets because each time I fired it consumed 1 9mm bullet. I have a video from the beta where you can see it in action.
I don’t know how to replicate it and I fixed it later on by removing the ammo from it. It happened when I had a smg equipped and drug the rocket launcher to the smg and swapped them in my inventory.