My 6721 came with a full auto carrier
My 6933 came with a full auto carrier also
My 6921 came with the "flat", no shroud at all carrier.
I don't (yet) have any rounds through these guns. Should I swap the 6721 full auto carrier into the 6921, and the "flat" into the 6721, since the 6721 is the more "common" of the weapons? Or should I just let them ride as they arrived from the factory? If I do swap the carriers can/should I swap the bolt also, or leave the bolt. I am ASSuming that headspacing isn't really an issue as all are brand new with no rounds through them. Any thoughts would be appreciated.