Im new to predator hunting. I just picked up an icotech gc320 on clearance for 70 bucks which seems to work pretty well. I am a big turkey hunter and build various turkey calls which led me to looking at predator calls on youtube. I ran across a shotgun whistle made from the caps of spent casings. It seemed to be more of a british fox huntinf thing, but i made one and it seems to mimic a rabbit decently. Anyone use these or the bent frame alluminum whistles with any success?