"What's it take to kill a turkey?" From the OP.
One well placed bullet, BB, or Arrow. Plain and simple. They are not some super tough armored bird. They die well from a well placed bullet, BB, or arrow. For shotgun I shoot 1oz #7-1/2's at them and have never had one get back up. We can't rifle hunt here for them. But a .17 in your favorite flavor would do just fine as a number of others have stated as well as .22Hornet.
