As inhumane as it looks for the poor little gophers -- I'm guessin' a garden gopher trap. I just hang noise makers and put out fake snakes.
To operate: Pull back the hammer and insert the safety, place a percussion cap on the nipple, load 10 grains of black powder into the barrel along with some paper wadding, put some peanut butter on the bottom of the trigger, place the device in a good location, set the sear, and finally, remove the safety.