The "Soviet" IIB Hurricane as a multi-role fighter-bomber had quite a few drawbacks. First of all, it was 40–50 km/h (25/31 mph) slower than its main opponent, the Bf 109E interceptor, at low and medium height, and had a slower rate of climb. The Messerschmitt could outdive the Hurricane because of the thicker wing profile of the British fighter. But the main source of complaints was the Hurricane's armament. On occasion, the eight or 12 small-calibre machine guns did not damage the sturdy and heavily armoured German aircraft; consequently, Soviet ground crews started to remove the Brownings. Retaining only four or six of the 12 machine guns, two 12.7 mm Berezin UBs or two or even four 20 mm ShVAK cannons were substituted, but overall performance deteriorated as a result.