One of my M4 style AR's occasionally gets stovepipe jams. I thought the bolt was closing too fast or the extractor was letting go too soon, so I've upgraded to a black spring insert, and just added a heavy buffer.
But I noticed something odd when I tried to upgrade to the heavy extractor springs from Tactical Springs. The extractor grips the case so tightly, that the ejector can't pop it out when I pull back on the charging handle to open the bolt! Maybe it would eject when firing, but I haven't tried it yet.
I have another carbine, and with the same extractor spring, the case will eject when the bolt is opened.
So, do I have a weak ejector or bad ejector pin on the one that "sticks"? Or might it be something more problematic like a bad bolt head recess...