Bofors 57x230R DATA

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’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.


So some minor news, the casing apparently weighed 1.1 kg. Also does anyone have any info for comparable shell so we can guess the HE filler?

I got some more info from a fellow IAA member but i have not been given the green thumb yet to share that info so im just gonna give away the basics. The HE shell had around 250 grams of HE filler, most likely TNT (trotyl). Its total projectile weight was around 2,45 kg. The loaded casing weight was around 1,5 kg. which puts the shell around 4 kg.

Not really my field but none the less interesting, however I’m not sure what a “mine” shell is?
I associate a “mine” as something concealed in the ground for a vehicle to run over or the enemy to step on.

Read here and here

Thank you.


Great drawings! Thanks a lot for sharing!

Ye i got greenlit.

@EOD do u know of any 57 mm AP shell which is similar enough to the one above so we can do comparative calculations to find out its average weight?

There is a British 6pdr that could fit.

Can u post a blueprint for comparison?

This is a photo (#4 from left). But this should be an almost solid shot (small tracer cavity).
It is kinda late here and I shall try to find something tomorrow. But can not promise to find anything.

Source: internet.

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Ok, could not resist to have a quick look and found it.
I see it is the MK IT and weight is given as 6lb 4oz 8dr.
Now find one to put this to civilized figures.

It seems to somewhat match up somewhat.

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I was bored so i did this.

I understood you wanted to see a similar design to figure weight of the one you are missing.
My guess is on 2300 gram.

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So i found these blueprints which apparently represents the Soviet 57 mm shells BR-271 and BR-271SP which were used in among others the SIZ-2 anti tank gun and ASU-57 assault gun.
They are really similar to the Swedish shell and i think i could more easily calculate its weight based on these. Can anyone confirm if these are BR-271 or not?

Presumably inspired by the de Havilland Mosquito “Tsetse” which was armed with a QF 6 Pr and Molins Autoloader.

Does the Whitworth thread form relate to the primer or the fuze?

-Does the Whitworth thread form relate to the primer or the fuze?