The original BFR was manufactured by D-Max. The Pistol was later acquired by Magnum Research and renamed the BFR. The serial numbers of the D-Max guns began with the prefix "DM". Magnum Research later re-engineered the BFR making it a much stronger, and smoother operating pistol. Prefixes on the improved models begin with the prefix "JT". The initial run of the improved models was chambered in .480 Ruger/.475 Linebaugh.