About the Type 99 20mm Mark 2 Cannon Model 4 “High Rate of Fire Version”

Machinery of War Discussion
1

Currently, three variants of the Type 99 20mm cannon are implemented in WT.

  • Type 99 Mark 1
    516RPM, 600m/s
  • Type 99 Mark 2
    490RPM, 750m/s
  • Type 99 Mark 2 Model 5
    750RPM, 750m/s
    (All feature in-game performance)

Among these, the Type 99 Mark 2 combines Model 3 and Model 4 into a single designation without distinction, but historically they differ as follows:

  • Model 3
    Drum magazine, 480 RPM, 750m/s
  • Model 4
    Belt feed, 500 RPM, 750m/s

Furthermore, according to Wikipedia, a “High Rate of Fire Version” of the Model 4 existed, and mass production and deployment had begun by the time the war ended.

  • Model 4 “High Rate of Fire Version”
    620RPM, 750m/s

九九式二〇ミリ機銃 - Wikipedia

Does anyone have any materials regarding this “High Rate of Fire Version”?
I think the following aircraft may be equipped with it.

  • A7M2
  • N1K2-Ja