Another cause for Failure to Extract
 

I have an Erfurt 1918 and not uncommonly, it will fail to extract the fired brass, resulting in a "stove pipe" jam. Sometimes it would fire a string just fine and other times, every other shot would jam. I tried a variety of things (different loadings, different magazines). Anyway, I decided to remove the ejector to inspect it (although the tip seemed fine-not broken). I discovered the problem! The ejector was not fully seated to the slide! Once the part was properly locked in place, the Erfurt functions flawlessly.....

Thanks for that tip, wonder if that contributes to same issue in S/42 36 model?

The specs of the ejectors is the same for both models