i have a shorty ar made with a sendra receiver and a military (unmarked) upper. this is a pre-ban gun.
i took this gun out today after it had sat in my closet for a decade or so. i gave it a cleaning, and checked out the internals before i gave it a fire.
every 2 or 3 rounds it was failing to eject. it was consistently turning the empty cartridge around backwards in the chamber, and would lock as it tried to feed another round. i did notice that when it succeeded in returning to battery that the brass was only coming out a foot or 2. i think my colt used to kick them out quite a bit further.
anybody have any idea where to start (besides a gunsmith)?
how do you check and, or adjust the extractor?
thanks for any replies and advice!

Sounds like a bad ejector. If the empty case is comming out of the chamber the extractor is working. Look at the bolt face, the ejector should stick out about a 1/16 of an inch. See if you can push it in and out. If it's flush with the bolt face it's not going to work. Either replace the ejector and spring or try to cleasn it. It's held in with a tiny roll pin and there is slight spring pressure behind it. I've had brass slivers stuck in mine before.

thanks for the idea Cletis. i checked it out, and the ejector seems to be working correctly.

the problem is, it isnt kicking the empties out. it is somehow turning them around "backwards" in the chamber? ive seen them stovepipe before, but not turn them around like this??????

Rifles that sit seem to have problems due to the fouling left in the rifle turning hard.

Cletis has touched on the ejector spring, so just buy a new black insert extractor spring (M-4) and be done with it.  Spent brass that is left in the action is due to the extractor dropping it before the carrier/buffer moves all the way back and is stopped by the end of the extension tube.

The other thing to do is pull the rifle down and apply a fresh coat of CLP to inner working areas of the rifle, including a blast down the gas tube to dissolve any fouling at the gas tube/gas ports, and the receiver extension.   On the chamber, use a 30 Cal mop soaked in CLP and spin it in the chamber to get the fouling that everyone misses; the build up at the last of the chamber cut just before the throat.  

thanks Dano, i cleaned it, and gave it a good soak in clp. i will let it sit until next weekend, then i will clean it again and see how she acts.
i will pay close attention to the chamber area, and post back if anything seems unusual.

thanks for the replies guys!

My guess is it is a ejector issue.  Stovepipes are an ejector issue. Brass being ejected short distances is an ejector issue.  I guess there is a small chance the the extractor is tweaked in some way that is causing problems, but I don't see how.

For the brass to be turned around, the extractor had to hold onto the rim long enough to clear it from the extension and allow the ejector to push it out and give it some rotational spin.  If the extractor was worn or too weak, the case would be laying in the reciever, extension, or most likely chamber, in the mouth forward orientation.

Your problem most likely stems from either the fact that the ejector spring is too weak or the ejector recess is too dirty.  Being that it has been stored all these years, my first guess would be harded deposits in the ejector recess that are slowing down the functioning of the ejector.  Easiest way to try to fix this is to either soak the bolt in solvent or CLP, or put a dab of CLP/solvent around the ejector and then work it in and out repeatedly with a empty case head (i.e. - hook rim under extractor and pivot case head onto ejector).  CLP would probably be the better choice though for this to work.  If that doesn't work then replace the spring.

Edited to add that there is also a small chance the ejector is bent, so that might need to be replaced.  You wouldn't think it possible for such a short piece of steel to get bent, but it happened to a friend of mine, although he was shooting a upper using parts of questionable quality.