My dad asked me for a simple hand gun mount for under the desk at home. We built this to work with both his Glock 19 and Glock 43.

Mount features 2 screw holes so it can be mounted to the bottom of a desk. We used a total of 6 magnets 14x3mm (3 rows of 2 that we had sitting around.

This mounts under any desk and holds the gun firmly in place but can easily be pulled off for quick access.

edit
I've added a 2nd file that allows for 3 rows of 3 magnets if you want something to have a big stronger hold.