Different profile barrel. Looks like a HB .690 ish tapering down to .750 @ muzzle. And yes they are in the mid-high $7's . The only up side to the Mini-14 or 30 is. They're CA compliant.
Which as a semi frequent traveler now that we're a short ride from the daughter is something to consider.

Going OT for a few.

One of my favorite "carbines" has been the Ruger 9mm Take Down PCC. Nondescript easily hidden in a vehicle, threaded bbl for (NFA friendly states) suppressor. Running a Sig Romeo in it that still affords use of iron sights.