I've just been watching the documentary series "Grey Wolves" about the U-boat arm in WW2. The second episode talked about the need to provide flak cover in Biscay for U boats coming and going from Lorient.

There was a clip of film showing Kriegsmarine gunners serving a twin-mount manual-loading AA gun. What surprised me was the small size of the shells. One of the gun crew had a bag of a dozen or more shells over his shoulder or round his neck and was passing the rounds one-handed to the loaders for each barrel. I would say they could not have been more than 50mm calibre. The whole thing looked a lot like the British experimental twin 6pdr AA, which never made it past the prototype stage.

I can't find any evidence that the 5cm FlaK 41 was ever made in manual-loading form. I can't find any evidence of any other German FlaK gun in this sort of calibre, or any similar French weapon that might have been recycled. There is of course no proof that the film clip was taken in Biscay, but it was definitely WW2 German on a warship of some sort.

Any ideas, anyone?

Probably a twin 2cm C/30 or c/38

Check this: http://uboat.net/technical/flak.htm

No these were breech-loading single-shot weapons loaded with single rounds through a manually-operated breech.

I think I've found the answer by looking at naval guns rather than AA guns. It must have been the Doppellafette 3.7 cm SK C/30.

I must admit I had no idea that the Kriegsmarine went to war with single-shot 37mm's as their primary "medium" FlaK weapon on larger ships. I just assumed that the automatic 3.7 cm Flak M42 would have been widespread, having been in production as the FlaK 36/37 since 1936. Indeed until a few minutes ago I had no idea they even had such a weapon.

Thanks for taking the time to look and respond.

Breech-loaded AA??? Perhaps it was a light deck gun used to defend against fast boats, or hit targets below the waterline?

Breech loading flak sounds like a nightmare. "Hans! Load faster!!!!"

Nothing odd about it, that is the 3.7 cm. SK C-30 gun. Pretty much the standard Kriegsmarine medium caliber A.A. weapon for most of the war. Usually came in a twin mount for surface ships, there was also a single barrel wet mount common to most early type IX U-boats

Ballistically and for reliability, the gun was good. Only in rate of fire was it lacking. Wonder what the outcome for the Bismarck would have been had it been fitted with 8 pairs of fully automatic Bofors 40 mm. replacing the C-30 mounts. (These guns were available, Sweden made money from both sides during the war.)

Off-site reference page concerning the C-30 gun.

http://www.navweaps.com/Weapons/WNGER_37mm-83_skc30.php

And a splendid 20 minute film on life aboard a large Kriegsmarine unit, in this case the Gneisenau. Probably done before the war began as the stern eagle and ship's bow crests are seen several times. These were immediately removed when hostilities started.

Note at 7:50 and 8:09 in the video - 3.7 cm. guns in exercise with older Luftwaffe aircraft standing in as targets.

https://youtu.be/VUJDNNfUrbY

The "Swedish" 40mm Bofors was license produced in many countries (on both sides) during WW II, sometimes with and sometimes without licence fees. Sweden had sold some to Poland before the war started and some of these probably ended up in Germany and got copied. The ones produced by Britain and the US had their carriages redesigned for ease of production.

From Wikipedia: https://en.wikipedia.org/wiki/Bofors_40_mm_gun
"Bofors also developed a towable carriage which they displayed in April 1935 at a show in Belgium. This mount allowed the gun to be fired from the carriage with no setup required, although with limited accuracy. If time was available for setup, the gunners used the tow-bar and muzzle lock as levers, raising the wheels off the ground and thereby lowering the gun onto supporting pads. Two additional legs folded out to the sides, and the platform was then leveled with hand cranks. The entire setup process could be completed in under a minute.

Orders for the land based versions were immediate, starting with an order for eight weapons from Belgium in August 1935, and followed by a flood of orders from other forces including Poland, Norway, and Finland."
and
"In World War II Germany, the Wehrmacht used a number of Bofors guns which had been captured in Poland and France. The Kriegsmarine also operated some guns obtained from Norway. In German naval use, the gun was designated the "4 cm Flak 28", and was used aboard the cruisers Admiral Hipper and Prinz Eugen toward the end of the war.[14] Beginning in 1942, several E-boats were equipped with the Flak 28 to enable them to fight against British MGBs and MTBs on equal terms.

Japan captured a number of Bofors guns in Singapore and put them into production as the Type 5."

The basic fact still remains though: Sweden did business with both sides. We sold iron ore (better than the local German ore) to Germany and got coal in return. We supplied the British industry with ball bearings and got some political advantages. We took care of British and American bomber crews after emergency landings. A crashed V-2 rocket was smuggled out to Britain. We assisted and trained Norwegians as guerilla fighters and later as regular troops. We allowed Germany to transfer troops from Norway to Finland.
In short: We played both sides in order to stay alive and not get occupied by Germany (no safe emergency landings for allied bomber crews if we had been occupied ...). During the last years of the war we had an allied signals intelligence unit stationed in southern Sweden. We also supplied intercepted German telephone and radio traffic to Britain (decrypted by a team led by a Swedish mathematician).

During the Vietnam war there were Swedes protesting outside the US Embassy at the same time as we supplied 84mm rocket grenades to the Carl Gustav weapon. This was done in two steps: Britain delivered from their stock piles to the US and we replenished the British supplies so thechnically we were not delivering to the US for usage in an ongoing war (the reality was another matter ..)

/ Robin