In some circles it was considered a travesty to tamper with the designs of Nikolov Stanislaw, but some of the head designers within the UEPC's Mobile Armaments Division felt that more could be accomplished with his design... and were puzzled why he did not design the unit originally as powerful as he could. To revise the Bulava, the UEPC MAD gave the design to Stanislaw's competitor for over fifty years- Matfey Sukhoi (descendant of the same Pavel Sukhoi who founded the aerospace industry in Russia from the 1930s). Sukhoi had a grudging respect for Stanislaw, and personally felt it was a discredit to his adversary to be asked to redesign his machine.
Rather than taking the vengeful course and destroying the reputation of Stanislaw's device, Sukhoi instead competed by making the design even more powerful no matter the cost. The result was the B version of the Bulava, which due to the political climate and desperation of the UEPC in their arms race, actually saw production in limited numbers.
The Bulava B is extraordinary for a number of reasons. Firstly, the idea of fixed weapons on an Axel is an uncommon idea that has been unpopular for an unspecified reason. Ever since the first fixed gun on an export version of the TR-7 Bear, turrets and other mounted weapons have been difficult to work with because it distracted attention from the pilot.
The second point of the Bulava's uniqueness is what makes the first point work so well: it has a copilot. Only in rare instances has an Axel unit ever had any sort of crew or operator other than the pilot, and almost always in experimental or unusual circumstances. Largely this was averted because of arguements between the pilots and their co-pilots in piloting the machine... but in this case, Sukhoi limited the co-pilot (termed the 'Gunner' in this instance) to operating the fixed turrets and operating a second set of hands.
These manipulator hands are the third point of the Bulava's strangeness... never before has an Axel appeared with such an arrangement. In theory the sub-arms are to allow for cargo-carrying and fine manipulations too fine for the main arms to perform. In practice, Gunners are not unknown for using weapons from a light Axel's arsenal to upgrade the firepower of their units.
The Bulava-B has seen limited deployment across the globe, and only the first production run has been completed. Though the Bulava-B outperforms it's immediate predecessor, the Bulava-A is still considered for mass-production over the B type because of the cut-costs and conventional design.
While the Bulava-A is typically nicknamed "The Hermit's Nightmare", the Bulava-B is often nicknamed "The Russian Kaiju".