I'm a little confused on the registration requirements on this item. Which part needs to be registered as the SBR? The Roni, or the the pistiol being put inside of it? One of the websites I visited made it sound like you had to register the Roni, but that doesn't make a tremendous amount of sense to me. On the other hand if you had multiple handguns of the same frame and manufacturer but different caliber, I could see where you might want to swap them in and out, and in that case it would make more sense (and be cheaper) to register the Roni instead of each individual handgun.
Any definitive answer on this (yes, I know I could just email the maker, but then I wouldn't be getting to know folks on here.)