If you put a ball in your musket then grab the muzzle you can remove the ball’s effect and hold it in your hand. I don’t think this is intentional since I can’t find any use for it, others can’t see you hold it, and if you fire the unloaded gun it still fires the ball. Also if you grab the effect from the hand that’s holding it with your empty hand it just stays in the new hand without grabbing until you grab again.
It’s not causing any harm and it’s kind of fun just carrying a black hole around but I figured you should know.