I don’t own a gun, but how about open carrying an unloaded gun, at the same time you are concealed carrying one with a round in the chamber?
Let the robber grab your unladed gun, then nail him.
I have seen different versions of that. Often, the open carried gun has the safety on, or is in a retention holser, and the person carrying it has a back up gun (BUG) concealed on his person.
There have been some documented cased where the BUG was used successfully.
“Let the robber grab your unladed gun, then nail him.”
If you kill someone under this circumstance, some prosecutors might charge you with premeditated murder because you made a gun you knew wasn’t loaded available to the shootee. The analogy might be that you laid a “booby trap” for him. Booby traps, especially lethal ones, are pretty much illegal.