In sources on the ZSU-37-2 Yenisey there is info on ballistic perfomance of its guns: projectile weight 0.733 kg, MV 1010 mps.

RoF of the Angara system (twin 500P guns) in the ZSU-37-2: 1048 rpm (so 524 rpm for a single cannon). RoF of the Shkval 4x600 rpm.

Frankly I tried to gather info on the ammunition for the Yenisey/Shkval just because I suspect that the Chinese somehow took advantage of the 500P cannon and/or its ammunition. There are some Chinese projects (eg. BJ-212 jeep, J-8 fighter, Luda-class destroyers etc.) that strikingly resemble projects that were cancelled in the USSR. The Chinese might have been given the whole projects for further development or they 'acquired' them a different way (and then reversed engineered them). Possibly the Type 76 naval gun (and 37x240 ammo) was 'inspired' by the Soviet developments of the late 1950s.

Piotr

That's interesting. The PLAN 37 x 240 is credited with firing a 725 g pro at 1,010 m/s, which is VERY close to the Yenisey.

NORINCO has offered a couple of mountings - the original H/PJ76F naval twin mount in 37 x 240 (RoF 360 rpm per barrel, apparently based on the OTOBreda Fast Forty / Bofors) and the much simpler "semi-automatic" AN3, available in 37 x 240 or 35 x 228 Oerlikon. This gun is based on the Oerlikon KDF and fires at 550 rpm. 

The pic shows a 35 x 228 round above a replica of the 37 x 240. The main difference in effect is that the 37 mm fires a heavier projectile at a lower velocity.