Fobus makes their kydex holsters to fit a variety of makes/models of handguns, and they also offer a stationary mount for the holsters. It would be quite simple to mount it somewhere handy on the tractor. Snap the handgun in when you get on, then snap it out and take it with you when you leave. I've considered riveting a nylon holster to my fender for carrying a handgun for shooting snakes and rats. I seldom bush hog without seeing a number of rats/field mice. A friend of mine has a leather saddle scabbard that he ties onto his loader mount in the fall in which he carries his .22 magnum for crows, rats, etc.