In September 1943, production of the GAZ-64 was superseded by the improved GAZ-67B jeep, which had a wider wheel base.[1] Consequently, the BA-64 was modified to accommodate the new chassis.[5] This alteration proved to be a major improvement for the BA-64, which was notoriously unstable on slopes due to its narrow track and somewhat top-heavy nature; the wider GAZ-67B track increased the vehicle's side slope angle to 25°.[2] The modified BA-64 was designated BA-64B by the Soviet government.[6] Other detailed improvements included firing ports, a wider range of armament and a new carburetor which gave better performance on low grade fuel.[2] Most BA-64Bs continued to be fitted with the same turret and 7.62mm machine gun as the original series; however, Soviet troops removed some of the original BA-64B turrets and replaced them with PTRS-41 anti-tank rifles[6] or captured German 2 cm KwK 30 cannon.[5] Another, more extensive, field modification involved removing the turret and even part of the upper hull, as well as adding a windshield salvaged from captured Volkswagen Schwimmwagens. This converted the BA-64B into an open-topped staff car.[2]