In its five years of service, the Bulava (both A and B types) has garnered a reputation for being a fearsome unit in the service of the UEPC. No other Axel was visibly proven to rip others apart, and this was a frequent scare tactic whenever Bulavas were ordered into combat. Naturally, the UEPC would want to find ways to improve the Bulava unit.
While the Bulava B was seen as a success in terms of up-armament, it cost more than the A model by two and a half times. The Bulava A itself wasn't cheap either, especially since it demanded exotic materials and had an unorthodox (and comparatively complex) skeletal structure. In preparations for an eventual lunar assault, the UEPC wanted to be able to manufacture a number of these units easily and quickly. The C model of the BK-47 was an attempt to make a production-friendly version of the Bulava A.
With Nikolov Stanislaw several years gone and Sukhoi unwilling to tamper with the design again, the project was passed to the in-house Mobile Armaments Division to find ways to make the Bulava "Friendly" to production purposes. This involved going over what little of Stanislaw's notes remained in addition to dismantling and examining a BK-47. After eight months' research, the team concluded that to retain the BK-47's capability the design could not change the skeleton or some of the major components. However, they were able to cut costs by switching from the exotic composites Stanislaw hand-made for the prototype to a Titanium-Durite alloy in the construction of the skeleton. Though this would decrease the Bulava's load-carrying capability and the unit's phenomenon durability, the drop in cost was deemed an acceptable trade off given the primary opponent for the C design were the LUNAR designs. The C version was put into production, with the first battalions walking into service two months after the incident at Palifca Satellite.
Though it's been some time since the C unit was put into production, no C unit has seen real combat as there are already many A and B versions in service with the standing UEPC forces, and they still continue to be produced in limited numbers. However, the C version has been selected for future variant modifications, which include a heavily-armored assault version and an artillery fire support version.
Eh, redid the Bulava. It always bothered me on the A sketch that the arm was in front of the right leg, breaking the pose. Decided to fix it here.
Not sure if I want this to represent the 'true' C version or not, since I thought there would be more modifications. However I couldn't justify any more changes... since the UEPC would rather have their unit terrifyingly effective than terrifyingly cheap (that's what the KR-14A is for).