Bf 109G 20 mm ammo capacity

[Jukka Juutinen]

Some sources say that the maximum ammo capacity of the central 20 mm gun of the Bf 109G was 250 rounds. However, some Finnish references state that due to feed problems like broken belts, only 130-150 round belts were used. Is there anything on this in German sources? If the same problem was noted in Germany too, why wasn't it solved in a way to exploit full capacity?

[Denniss]

200 rounds capacity is stated in the manuals
135 rounds is for gondola guns
it's possible the Finns used less ammo due to arctic weather conditions, having a safety margin or to reduce weight/ammo consumption?
Noticed they also used less MG ammo

[Jukka Juutinen]

The Finnish source (a book on 20 mm guns in Finnish service) states that the reason was reliability, not saving. And nothing to do with Arctic since it was around the year practice apparently.

[Broncazonk]

Gunther Rall spoke on camera about 20 mm link reliability (and the lack thereof.) The interview was on US television (years ago) and it may be on youtube. (I will try to track it down.)

https://m.youtube.com/watch?v=STFdRrWBW2w

I *think* Lipfert talked about it in his book as well.

Bronc

[Jukka Juutinen]

In that video Rall refers to the wing cannon, not the central cannon. I will have to check the book, but it was, I recall, that full belt was heavy enough to cause it to break when pulled by the feed under high g. The question is: Why there was no belt-booster in the belt container to compensate for the pull.

[Jukka Juutinen]

Here is what the Finnish source states:"Regarding the reliability of the MG 151/20, a memo dated July 1943 stated that there are no complaints as to the gun itself, because the most common problems are the ammunition and belt. There several cases reported in Finland in which the cartridge case had sheared in two in the chamber or the extractor had ripped a piece off the rim. The suspected reason being soundly the weakness of the steel used for cartridge cases. Another mode of failure was breaking of the belt. It was thought to be caused by too a heavy belt when loaded to the full 230 rounds. In thesecases the belt typically broke at half-length. The memo contained information, according to which Germans were loading the Bf 109G with only approx. 130 rounds. Similar problems were reported on the MG 17. To prevent belt breakages it was instructed that belt containers be equipped with movable wooden strakes. Despite these it became a regular Finnish practice to load the container with only 130 founds with a further 25 rounds in the feed chute... "