Conker
The sportster only comes in rimfire rounds , The 22 Lr 22 mag 17 HMR and 17M2 . If you want anything larger you need to go with the handi rifle .
The sportster frame has an offset firing pin that will not work with centerfire rounds and the frame would not handle the pressures of a centerfire anyway .
By the way , Welcome to the crazy world of H&Rs and GBO