Been more on the receiving end too but I only called it myself once for someone who was trying to gain entry to my house without my permission. It was a guy looking to kick the shit out of my brother (he was high and my bro owed him money) and wouldn't believe that he wasn't in the house (I was the only one home).
I told him to leave, he wouldn't, I called the police and let them hear him yelling and banging on the door. Once I hung up with them, I got my rifle off the rack (checked to make sure it wasn't loaded but put some ammo in my pocket just in case) and told him if he didn't leave before the cops got there, he was going to be sorry. He thought I was bluffing till I pulled the curtains on the front door back with the barrel of the gun. Then he cooperated and hauled ass off the property. I filled out a police report and my neighbors all witnessed it. I left out the part about the gun.