Emu, you did not say what you would be shooting them in, so it depends......
I don't hunt turkeys, but I have killed tougher animals with standard H&N Baracuda and JSB Exact King pellets and they do just fine. All my pellets have passed through animals like skunks, jackrabbits and prairie dogs at any body angle from any distance. I stick with the domed pellets because of the better accuracy and retained energy advantage. I have tried Beeman Silver Bear and H&N Crow Magnum pellets, and the accuracy loss was unacceptable and I have had no problem with the domed pellets being deadly at .25 caliber.
If you were shooting turkeys with a chest shot with standard Baracuda pellets at the 40-45 FPE I shoot at, it would be a pass through and the turkey would probably be DRT. I have shot sharptail grouse with JSB Exact King pellets right through the heart, and they fall dead without so much as flapping a wing.