Perazzi nomenclature is odd at best. Back in the old days they made a run of MX8B guns which were mostly 30" flat rib guns, 12 ga designated pigeon guns and were sold at a discount as compared to a plain/standard MX8. They still even seem cheaper on the used market today. Many of those guns had a choke tubed bottom barrel (columbaire?). It makes no sense to me why a B gun was/is cheaper when they are virtually the same gun as a standard MX8?? Like Stan said, there are many flat rib guns not designated as "B", but when used it means flat rib no matter the gauge.
