Historical database known problems

1. Breda Ba.27 (first flown in 1933) is armed with Breda-SAFAT machine guns which were developed in 1935. Therefore, earlier versions of Breda Ba.27 had a different armament? Or some of the dates are incorrect?
2. Berezin UB was developed in early 1941 but Il-4 is listed as having Berezin UB in 1939. Precursor of Berezin UB? (resolved)
3. Neubaufahrzeug - a German heavy tank - was produced in 1935 but listed as main weapon 7.5cm KwK 37 developed in 1937. Which gun was actually installed on its early prototypes?

[TheWaltsu]

Berezin UB was developed in early 1941 but Il-4 is listed as having Berezin UB in 1939. Precursor of Berezin UB?

Actually, Il-4 was produced during 1942-1944. It's precursor would be DB-3, which uses 20mm ShVAK cannon and ShKAS machine guns. DB-3 was produced during 1936–1939.

[Oleg Nizhnik]

In this case, bomber Il-4 with Berezin UB is from 26 March 1942, torpedo bomber Il-4T with Shkas and Shvak - 1 April 1940. I am not sure where to draw the line between DB-3 and Il-4, seems naming change was applied even to some of the already manufactured DB-3