So here i am once again with another thread discussing rare Swedish ammo. This time it is the Swedish 57x230R cartridge, historical designation 57 mm skarp patron m/47 (57 mm sk ptr m/47). As you might know the Swedish air force ammunition manuals prior to like the 80’s totally lacked data on all ammunition. It only showed color codes and cross sections. So that is why i’m making this thread.
This 57x230R cartridge was used on the Swedish 57 mm akan m/45 cannon (sometimes called the m/47) which was a load out for the T 18B. It could fire three types of ammo according to the ammunition manuals of the time, 1949 & 1957. Those being HE, AP and Training.
According to different sources each cartridge weighed about 4 kg with the projectiles weighing in around 2,5 kg. This is reasonable looking at similar shells but not very specific. According to the book Flyghistorisk revy nummer 31: Saab 18, it had 3 high explosive projectiles, one with 180 grams of he filler, one with 250 and lastly a mine shell with 400 grams. Note that only one HE shell can be found on the ammunition manuals.
As for velocity it gets worse. The airwar.ru’s article on the gun says that the velocity was between 686 - 744 m/s. Anthony G Williams article on the cartridge says 744 m/s for the AP shell. As for Swedish sources the book on Swedish aviation weapons 1932-60 says that its velocity was ca 800 m/s at ground level. It is written by the Swedish air force main weapon engineer of the era Nils Thorsson.