No, I haven't heard of that before on a sportster. I've heard the original run of 22lr barrels from nef came with the larger .224 bore (22mag, 22 hornet, 223, etc.) not the smaller .220 (or whatever it is) 22lr bore.
I'd call NEF in the morning, tell them what you found, and ask if you send it in if they'll replace the barrel (they will) and while it's there you might as well get a free trigger job and pay, what is it $58, and get a bull barrel 17hrm barrel fitted (or sportster 22mag or bull barrel 22 mag). :wink:
Then you'll have a good shooting 22lr, 17hmr (and/or 22 mag), and a crisp trigger.
That's probably the easiest fix.
later,
scruffy