On the Lead Adventures forum there was a question about the sdkfz222 and the Clockwork Goblin Spinne mech.
I do not possess a 1/56 scale SDKFZ222, but I do have a SDKFZ253 and the SDKFZ250 has a variant fitted with the 222 turret, so is usable for a comparison.
SDKFZ253 and Spinne mech.
Spinne turret on 253 vehicle.
Spinne turret compared to Warlord Games 37mm PAK.
I have replaced the auto cannon with an MG, as I feel that is more in keeping with the vehicle.
The 37mm gun does need some detailing, recuperator under the barrel and a more detailed breech and recoil path protection, based on the Warlord item.
Might check out the spare bits from the PSC Russian gun set.