A large-frame single-action Revolver designed and manufactured by Magnum Research, modeled after the Ruger Blackhawk. The BFR is available in a myriad of different pistol and rifle calibers, and can be custom-ordered in various barrel lengths. Short and long cylinder versions are also available, depending on caliber.
Officially, "BFR" stands for "Biggest, Finest Revolver", though many colloquially refer to it as "Big Fucking Revolver."