i give the turkey 30-40 seconds to expire on its own. if you put a vital hit on the turkey it will expire less than 30 seconds. if worst comes to worse grab the turkey's 2 legs in your left hand then use your right knee to pin down the flapping wings, flip out your knife and slit its throat. that is the fastest most humane way to kill a wounded turkey.
good luck.
all im using this year is a bow. have fun trying to draw back on them!!!