Well, after doing *some* research I bought some Remington 5.56 ammo for my AR-15. Went out shooting this past weekend and about 60+ rounds into shooting, I get a shell stuck in the magazine.... couldn't get it out. I also noticed that the residual smoke smelled really pungent, almost enough to make you sick! This was cheaper ammo but not that cheap... I thought Remington ammo would be Remington ammo - I guess I have a lot to learn about ammo for this AR. Reloading never sounded so good.
Anybody have any insight on why this smelled so bad or why (possibly) I have one stick in my barrel? I've NEVER had a case stick in the mag, and yes, it was a clean rifle before I broke it out.

what kind or AR is it? does the barrel say .223 or 5.56?  LC XM193 smells some too, but i dont mind

Where is it stuck?  in the chamber or the mag?  Just to be sure: The chamber is where it sits when fired. the magazine is what holds the waiting rounds.  

A clip by the way, holds rounds together but has no provision to feed into the chamber, it is just a faster way to load the magazine.

the 223/5.56 thing is not your problem, more info is needed to determine what is.

open mouth, insert foot... sorry, yes, it was stuck in the chamber.  btw, the AR is a dpms kit gun, which should take both rounds (part of my research).

i took a cleaning rod to it last night and the shell literally fell out, seems strange it didn't come out normally.

I guess I was wondering if ammo marked 5.56 used cheaper powder... any ammo I've bought labeled 223 never smelt like that!

interesting, will do!

I have a DPMS 308 and had to get the chamber smoothed.  I like the rifle though. Thew reason it came out so easy with the cleaning rod is it had cooled down by then.  

I really think you should send it to DPMS rather then do anything yourself or have anyone locally do it.  their 800 # is on their website.  Talk to Shane he is very nice and knowledgeable.  Like most companies DPMS has a moron or two working there, so don't risk getting that person talk to Shane.  Also, ask about time frame.  They turned it around in less then a week because I asked them to.   If shipping is a problem for you ask them to send a call tag (or pick-up label).  
Don't let it slide to see if it will go away or tinker with it to see if you can fix it, just get it taken care of and move on.

Rough chamber or timing issue.......