i like use my bow for turkeys for the extra chalenge. but they are a tuff bird so if you are just atarting out i would go with the 12 and 3 1/2 mag

i too shoot a 12. if you try 3 1/2 inch heavy shot be ready for the recoil. you wont notice it when hunting but but it kicks like a mule at the gun range.

Yup, 12 gauge with an "extra full" turkey choke tube. Not to be confused with just a full choke tube. Unless of course you don't mind spitting out pellets when eating the bird. I only use 3" shells in #4 or #6. Either will work just fine.