IMO, mounting a handgun in a vehicle is a foolish idea. It is too tempting to run into the local Stop & Rob, "just for a minute" for a slurpee or pack of smokes, and leave the gun in the car or truck.
I know of cases where folks have their gun in the car, somewhere, and jump out after being involved in a wreck. It is not uncommon for folks involved in wrecks to be intoxicated and violent. Where's your gun?
If you want to mount it because carrying is uncomfortable, perhaps you should consider another method of carry.
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