Yes, you can install it wrong. It only fits in 2 positions, correct and incorrect (which is 180 degrees off).
See below link for a video of how to disassemble and reassemble it. However, if the OP took it apart to clean, they can do the same, but rotate it 180 degrees this time.
http://www.brownells.com/aspx/NS/Gun...&p=0&t=1&i=866
Wow that's crazy. As many times as I have taken them apart I never thought of it. Thanks all
NObama 2012
Yes it is extremely possible to install the extractor 180 degrees off. I know on my M16 the bolt had a relief on the sides of the pin opening for visual reference to ensure proper installation.
Nitromethanol and Spent Gunpowder....best two smells in the world
The microwave takes about 4 minutes to pop the popcorn so I had some time to kill. The bolt in the pic is backwards, and neither the S&W M&P15 nor Colt 6920 bolts can be installed that way.
My first time firing my DPMS I had it in bassackwards...Fortunately there was someone at the range familiar with the platform and helped me extract the casing. Two days later I was nowhere near breaking it in, and burnt to a crisp!
Disassemble the bolt assembly, give it a good cleaning, and when you put it back together make sure you put it together correctly. Definitely sounds like an extractor problem, possibly either a weak extractor spring, or a missing spring.