Hispano and Oerlikon Type ammunition development

Machinery of War Discussion Historical Discussion
1

It always bothered me that French Hispano-Suiza 404 Cannons use the same ammunition as the British Hispano 20mm cannons. The same ammunition is also found on the Swedish Fokker with twin Oerlikon FF cannons.

Does anyone have any information about the historical development of Hispano and Oerlikon ammunition?

I know that Britain only used Ball and maybe explosive rounds at the early stages of the war and later developed AP and SAP-I rounds.
Same with early British (and German) planes, French planes therefore shouldn’t have access to later developed ammunition types like SAP-I.

I would also assume that early explosive rounds were just HE instead of HEI, since most nations later added incendiary compounds to the shell or gave the explosive incendiary properties.

Japan also used the Oerlikon FF in form of the Type 99-1 cannon, which as far as I know came with foreign Ball, AP and HE ammunition as well as domestic developed rounds.

2

Someone else that noticed?
Also the swedish Oerlikon FF in game is also wrong, it should be on pair with the Type 1 and MG FF, the FF L was the longer powerfull one which the in game FF has the stats of.

3

I found this in a French manual for the cannon. Dated 1939.
French_Hispano_404_ammo

So we have:

  1. Practice
  2. Tracer
  3. HE-T w/ and w/o self-destruct
  4. HE
  5. AP
  6. AP-T
  7. APHE
  8. HEI

Now we only need some data on the actual shells :)

4

Here someone talks about a French HE shell with 10g of Pentolite.
Muzzle velocity was probably 880m/s all across the board with 35g powder.
The British SAPI used ~32g according to a drawing in the same topic.