Sorry you're having so much trouble! Last year I purchased a new P380 and compared the extractor chains of and old vs the new. Here is the thread. Note the rear pin is much shorter. skiflydive mentions how people have shortened their pin. This is what he is referring to but it looks like new production incorporates a shorter pin. Long story short, too much tension on the extractor was preventing proper and efficient feeding. Your fail to fires were mostly caused by the gun being slightly out of battery.
http://www.kahrtalk.com/showthread.p...ain-Old-vs-New
Kahr P380 x2
Kahr K9
Kahr CM45
Sig P938
Sig P365 x2
Sig P322
1911 Range Officer 9mm
M&P 9mm