Hi Jon, NEF choke threads are already in some 20 gauge barrels right from the factory. It is the same as a Win-choke thread or a Browning Invecta,[NOT the Invecta +] . These threads are put on a bunch of different offerings by Carlsons,Kicks,HS,Tru-Glo,Truelock, Puregold and Cabelas. A variety can be found at Gander Mountain too.They will offer tubes that are for steel only so don't get stuck with one of them. Some are specifically stated to be for Hevi-shot. All of these will come in a wide range of constrictions designed to cover all shooting situations . You're after Turkeys so you'll want to go as tight as possible . Now comes the crunch. Do you want to have your girl shoot that gun after she fires her first turkey load? If so, YOU evaluate what she will be treated to. Those choke tubes all come with extended and ported versions for what they're worth in reducing recoil. Noise ,for the observer is annoying but that shouldn't affect her. Do EVERYTHING you can for her so she'll come back and be your hunting buddy