WNC, all the rimfire barrels available from HR1871 will fit the sportster in general but as Nuttinbutchunks says, they may not fit good. The best advice would be to send the frame in for a barrel to be fitted. They charge $15 for barrel fitting and $10 return shipping, as you probably already know. If you have the option of buying a barrel from someone, just send NEF an email asking them if you can send the frame and barrel in for fitting. Email them at hr1871@hr1871.com or give em a call at
(978) 630-8220
Tim