[Juha]

Hello
I don't have a slightest idea who Koch is but in general different ammos had different weights and different muzzle velocities. For AA guns the AP shell, German APs had usually a small burster, was usually heavier than the HE round and so had lower muzzle velocity. But then Germans had also special AP rounds with heavy penetrator casted inside light metal jacket which were lighter (was that called Composite Rigged or not in English, sorry I don't have time to check) and had higher muzzle velocity. IIRC 20mm and 37mm gun models used same ammo so, I means 20mm Flak 30 and 38 used same ammo and 37mm Flak 18, 36 and 43 used also same ammo, so their muzzle velocities with same type of ammo should be more or less same but Flak 38 and Flak 43 had higher cyclic rates than their predecessors. In automatic guns there are at lest 2 rates of fire, theoretical and practical. The latter included the time needed to change magazines when they emptied during firing. So one must check from the sources that one is comparing same facts when trying to compare the figures. On 88 the Flak 41 was a different gun than the earlier models with much higher muzzle velocity and ceiling and of course with greater range. On 88s the rate of fire depended from the crew, highly trained men in their 20s could fire faster than young schoolboys or old men working as temporary crew. And of course a crew could keep their max rate of fire only for a rather short time before geting tired but I don't know if that had any practical effect in prolonged firing or if they ran into cooling problems if they could keep 20 rpm firing rate for a long time.