I've found that the mere sound of racking a pump action shotgun is a HELL of a detterent. Used? Well, if warning shots count, then yeah. I lived in an apartment in a bad neighborhood and had a .357. One night some jackass came over the fence into my teeny tiny patio while I was in the shower, I chased him, bare nekkid out the door, gun in hand and fired a shot into the ground as a combination warning/threat/call for help. I have never seen anyone run so fast.