I agree with buckalley. While I am not a fan of mechanicals for deer, I do believe they are the way to go on turkeys, where we are not as concerned about penetration and actually want to minimize it in most cases. The mechanicals he is referring to from NAP are called "Gobbler Stoppers" and come in both 100 and 125 grain sizes. The blunt end gives more shock on impact and work much better than regular mechanicals or fixed heads when hunting turkey.
I was lucky enough to get my first turkey with one last year and it performed nicely, knocking the turkey down in its tracks with a short expiration thereafter.