on any single action autopistol,worn cocked and locked. I even weldedsuch shape extentions onto PPK's, P35's, Stars, because they shield the cocked hammer from blows, help prevent snagging on clothing, and they "guide" one's hand onto a proper firing grip, during a fast draw.
If the bottom rear of the trigger guard is "undercut", the ducktail also lets you grip the gun "higher" on the butt, which helps recoil-control. The "lower" that the gun sits in your grasp, the less leverage it has against your wrist, in recoil. This is one reason that revolvers are harder to control than are good autos, given guns of the same size and wt, same load-momentum (bullet wt and velocity).
If the bottom rear of the trigger guard is "undercut", the ducktail also lets you grip the gun "higher" on the butt, which helps recoil-control. The "lower" that the gun sits in your grasp, the less leverage it has against your wrist, in recoil. This is one reason that revolvers are harder to control than are good autos, given guns of the same size and wt, same load-momentum (bullet wt and velocity).