40mm Bofors gun operation mechanism question

[russianammo]

My name is Chris and I am from Austria. I am a specialist in Soviet and Russian ammunition and I am the author of the Russian Ammunition Page at:
http://www.geocities.com/russianammo

Currently, I am researching the Soviet 37mm M1939 anti-aircraft gun, which is more-or-less a copy of the Swedish 40mm Bofors L/60.
I would like to make a description of the operation mechanism of this gun and one of the threads in this forum helped a lot.

However, I still don´t understand how the cartridge charger clip is ejected from the gun´s mechanism.
How can the clip move down together with the cartridges without getting into the way of the fired cartridge case?

As far as I understand the fired case is ejected rearward between the loading tray and the two feed rolls. This happens before the two feed rolls feed the next cartridge onto the loading tray.
However, when the incoming cartridge is supplied, what happens with the cartridge charger clip?
Does it remain stationary inside the feed mechanism?
This would, however, also mean that all cartridges are unlocked from the charger clip as soon as the clip is inserted into the feed mechanism. Because otherwise the following cartridges cannot move down without the charger clip.

When and how is the cartridge charger clip ejected? Does it move sideways, out of the line of the ejection chute?

I would very much appreciate if somebody could bring some light on this!

Thanks very much in advance!
Chris

[Godwin Hampton]

Chris,

As you said, the rounds ( cartridge + shell ) are in clips of four, each round locked by a spring-loaded hook at the base. The hook's other end is a button protruding from the front face of the clip. As the autoloader pulls the rounds down towards the feed rolls, the clip travels in a groove down the autoloader's curved rear guide. This groove becomes progressively narrower at the front, forcing the buttons inward and releasing the hooks' grip on the cartridge. Thus the rounds are one by one freed from the clip, which then falls at the feet of the loader through an aperture at the side of the autoloader. Two grooves and apertures are provided, one on each side, so that the clip could be loaded facing any side you like. Some British Army guns had the right aperture sealed off, but the reason for this eludes me.

Hope this answers your question,

Regards, Godwin

[Tony Smith]

Originally posted by Godwin Hampton
As you said, the rounds ( cartridge + shell ) are in clips of four, each round locked by a spring-loaded hook at the base. Godwin

This shows the retaining claw in the open and closed position:

[Tony Smith]

Originally posted by Godwin Hampton
As the autoloader pulls the rounds down towards the feed rolls, the clip travels in a groove down the autoloader's curved rear guide. This groove becomes progressively narrower at the front, forcing the buttons inward and releasing the hooks' grip on the cartridge. Thus the rounds are one by one freed from the clip. Godwin

Here you can see the clip being fed into the Autoloader, and the ramp which lifts the retaining claw buttons as they are drawn down.

[Tony Smith]

Originally posted by Godwin Hampton
Thus the rounds are one by one freed from the clip, which then falls at the feet of the loader through an aperture at the side of the autoloader.
Godwin

As the full clip of four is fed down into the Autoloader and the ramp lifts the claw, the rounds do not actually separate from the clip until 3 rounds have been unlocked, when the clip is moved to the side.

[Tony Smith]

Originally posted by Godwin Hampton
Two grooves and apertures are provided, one on each side, so that the clip could be loaded facing any side you like. Some British Army guns had the right aperture sealed off, but the reason for this eludes me.
Godwin

When the 4th round is unlocked, the clip falls out the side opening in the Autoloader.

The 2 apertures only seem to have been used on Naval guns, as all the Army Bofors I have seen only have 1 opening on the left side of the casing.

[russianammo]

Godwin and Tony, thanks very much for your help! The pictures and explanation leave no questions open ....!

Chris

[Stellan Bojerud (RIP)]

Originally posted by russianammo


Currently, I am researching the Soviet 37mm M1939 anti-aircraft gun, which is more-or-less a copy of the Swedish 40mm Bofors L/60.

Yes, but in fact the Soviet 37 mm M/1939 is an upscaled version of the Bofors 25 mm M/1933 which the Soviet Union bought from Sweden.

[alleramilitaria]

tony
great shot of the boffers...
on a side note just about 100m from that gun i picked up some rare carrier tools at the antike shop in that town.
the little place had a outside area and there were some huge /|\ marked 1940 dated spanners. i had a great time bring them back as checked bags (i guess the set of carrier sprockets helped too).

[Tony Smith]

Originally posted by alleramilitaria
tony
on a side note just about 100m from that gun i picked up some rare carrier tools at the antike shop in that town.
the little place had a outside area and there were some huge /|\ marked 1940 dated spanners. i had a great time bring them back as checked bags (i guess the set of carrier sprockets helped too).

You're welcome, Dave, but you probably paid too much. We have so many original carrier tools and NOS parts scattered around the country that they can be bought as fishing sinkers in Bait shops, and as garden ornaments in Landscaper's Suppliers.

[alleramilitaria]

2 BIG wheel spanners dated and marked ..... $10.00 au or $3 USD

[Stellan Bojerud (RIP)]

I beleive only one Army 25 mm AA gun m/33 was made. There were however several Navy 25 mm AA guns m/32 produced.

The Soviet Union bought at least one 25 mm m/32 and license rights. The engineers L.A. Lokev and M.N. Loginov of No 8 Artillery Factory near Moscow made an upscaled version in 37 mm known as M 1939.

These were also produced in large quantities by factories 4 Krasnojarsk, 8 Moscow and 586 Kolumna.