Yah I'm going to go with the 4:7:1 from Marlin. Now that I've looked into it more marlins 4:7 look stronger than advanced adapters 5:1 which are really 4:97:1. About the other guy's reply there are 5:7:1 gearsets I think AA makes them but I'll find out tomarrow. Inchworm sells AA products and Marlin products and vise-versa. Marlin sells Inchworms built Leftys. Inchworm did create the quad drilled flanges though and some other good stuff. I still need to do more looking into all of this.