A jerky gun is a hand-held press used for making strips of meat jerky from ground meat mixtures.
It consists of a tube, with a press, and interchangeable tips: a flat tip for strips of jerky, a round tip for sticks.
To use, you mix ground meat with some spices (either your own mix, or a purchased packet, such as those from American Harvester, which includes a cure for the meat as well), and put the meat mixture into the jerky gun. You then press it to extrude the meat, and then dry the strips in a food dehydrator.
Further reading: Safe preparation of jerky (National Center for Home Food Preservation)
You must ensure that the meat reaches a temperature during the drying process of at least 71 C (160 F) to eliminate the risk of any E. coli.
See the National Center for Home Food Preservation’s site for safe, lab-tested directions on making jerky.