sherpa holster for the 1911. The gun locks into it, you have to depress a finger tab while drawling to reilece it. Would make it difficult for someone to just grab it.
I own a serpa. While I trust its retention for hiking about the desert, I would not rely on it to keep my pistol away from someone trying to remove it from me for few reasons. The button could easily be depressed accidentally during an attempted grab, the nub that retains the pistol is pretty small and could fail, the connection between the holster portion and the belt attachment/paddle is another possible point of failure.