At the range recently with my Oly pre-ban jam-o-matic.  I was using well-used USGI 30's and L.C. M193 ammo.

After firing a few shots, I could feel that the bolt hadn't gone back into battery, so I unshouldered the rifle and took a look.  It looked like a round had been partially stripped from the top of the mag and had its nose jammed into the locking lugs.  Forward assist would not move it, so I ejected it.  Again, bolt moved forward, partially stripped a round out of the mag, and stopped.  This time I looked a little closer and could see a live round in the chamber.  So it seems as if the problem started when a spent round was ejected, and a live round was chambered and somehow another live round was also picked up out of the mag.

This happened with a couple different mags, but I didn't have them marked so I can't say how many mags it happened with.  The problem occurred several times throughout the day.  Is it the mags or is it yet another problem with the Oly?

FWIW, be careful eswanson, as IF there was a live round in the chamber, (and not a fired round, extractor fail'd to extract) and you use the forward assit to attempt to force the jammed round up into the already loaded chamber, ya could get the surprise of your life, should the nose of the fmj round set-off the live round chambered, [b]WHILE THE RIFLE Is NOT IN BATTERY[/b], a very bad thing....

As to the fault here, does it do this with all your mags, if it does then I'd start by checking the extractor (seems your post indicates some work fine).

Should extractor spring and blue spongy thingy (technical term) looks okay I'd check the ejector next.

A piece of masking tape on the bottom, w/ a number on it will help w/ identifying bad mags from the good ones, if Oly runs trouble free w/ one or more of your mags, (and run 50-100 rnds reloading same mag to check) then that would lead me to believe some of your mag springs may have gone flat and need replacing....

Mike

PS - be careful, we don't want ya making the KAboom News. [;)]

Oh, believe me, I laid off the FA when I realized there was a live round in there.  

It's not that a round isn't being extracted, because the round in the chamber isn't fired.  It's literally as if it's chambering one round, then going back and trying to get another one.  (I know it's not actually doing that, but that's what it seems like).  Why would a flat mag spring cause that?  Seems like a flat mag spring would cause the bolt to override the round in the mag because the spring isn't pushing it up enough.

While it may very well be the mags, let's assume the mags are fine for the moment.  What problems with the rifle could possibly cause this?

Really, I'm not trying to be a PITA.  I'm just getting a little fed up with the feeding problems on this gun.  I'm at the point where I'm thinking about sending the lower back to Oly to be replaced with a same-serial number, new lower and starting over.

When the mag spring goes soft, the round is not held tightly/firmly against the feed lips.  As the carrier/buffer comes back and makes contact with the back of the receiver extension, the jolt will pop the top round out of the mag, and then when the bolt returns forward, the bolt picks up another round out of the mag, hence the double feed.

To fix the problem, check the mag springs and the mag lips to make sure that they are not being spread open by the force of the loaded rounds.  A new spring and simply bending the mag sides in a little at the middle of the mag (just forward the feed lips) usually solves the problem (if the feed lips are not cracked at the back/bottom of the U channel).

Also note,  the CARs have a little more trouble with questionable mags due to the jolt being harder that on a standard butt stocked rifle.