One CAN make jerky from hamburger, BUT....... be very careful on the hamburger you choose!! Because it doesn't get hot enough in a dehydrator, it won't kill the bad bacteria that can often be found in hamburger nowadays. IF you DO use hamburger, get it from a place that grinds their own beef. For God's sake & YOURS, don't use those "chubs" that come from the meat packing plants!! You'd be better off getting a rump roast or some other fairly lean cut of beef and slicing it. Walmart used to carry a fairly decent jerky seasoning.
As far as I'm concerned, the guns are OK, but a waste of money, all in all. One can do the same with waxed paper and a rolling pin.