Hit the range today(indoor, and yes, it was cold) and put about 200 rounds through the M&P15-22, and some .45acp downrange. This evening I opened up the rifle, wiped it out, cleaned the bolt and lubed the rails, reassembled, pulled back the charging handle and released.
Whiskey tango foxtrot?!? What the hell was THAT?
Pulled back the bolt and there's a spring loose in there! It seems when the bolt dropped the extractor exited for parts unknown. I still can't find it.
Looks like there'll be a call to Smith & Wesson in the morning.