We did somewthing similar in the early seventies.We had an officer killed with his partner's gun,and many of us started carrying the first chamber empty in our revolvers.
Gun grabs were quite common then.We knew that if we had to shoot it would take two fast trigger pulls to fire,but we didn't feel disadvantaged by that.
We felt that if the revolver was snatched,it would surprise the miscreant long enogh for us to move and access our back up revolver.Fortunately no one ever had to prove the theory,but I still think it was a good idea for those times.

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Blessed be the Lord,my Rock