Hi Guys. I am very new to the Ar world and am learning as I go. I have a new AR-15 with a 10.5" brl. Fired approx 5 rounds down range and it has stopped ejecting properly.  Loading the mag up with a single round results in the spent casing more or less sitting on the mag after firing. The bolt does lock back. With several rounds in the mag  and the rifle fired there is a jam between the empty casing and the new round. Using American eagle 55gr .223  FMJ boattails.  Loading the Mag up and manually cycling the live rounds thru results in no problems at all. Everything is loaded and ejected properly. Any Ideas would be greatly appreciated. Rifle was cleaned before going out aswell.

Sounds like the extractor is lossing grip on the spent case rim during ejection, and not staying of the face of the bolt until end of stroke.

As long as the ejector is moving freely in the bolt (read not binding up), here is the solution (read band-aid).

Go to a hardware store and buy a #60 O ring (plumbing supplies).  Pull the extractor, and add the #60 O ring around the outside of extractor spring.  The O ring will add tension to the extractor, and should resolve the dropped spent case problem on extraction.

I would suggest a simple change of extractor and ejector spring.  I would recommend trying either a heavy Colt spring with rubber insert with an O-ring as Dano523 advised or buy the Defender Ring (in place of the o-ring) for quite a bit more money.  I would also replace the ejector spring.

A quick test for the function of either spring includes removing the bolt carrier from your upper.  Try to push the ejector outwards.  You should feel a strong resistance from the spring (very hard to move).  Also press the ejector spring backwards.  Your finger nail should bend before the spring moves much.  

If either spring is weakened this is a major factor in the extraction and ejection.  They are also the least expensive fixes.  Do a search on this subject there is a lot of discussion.  Do not drill the gas port out unless it is a last resort and then seek further advice.  

I had a Kitty Kat upper that would not run.  I took it to a couple of C3 dealers and had no luck.  I even sent the upper along back to DPMS.  They found it worked all the time on their lowers with their bolts.  I got to the point of drilling out he gas port.  I did it step by step and then had it running.  The recoil impulse was A LOT.  I called them on this and they did not have an answer.  I took a friends AR and tried the upper on it.  It ran like a champ, still strong impulse.  I took his parts out and put them in mine and it ran like a champ.  I detected a VERY NOTICABLE increase in drag about 1/2 way back when cycling the carrier with my parts in my gun or his gun.  I called DPMS on this, hoping they would help out, and they said send them the complete gun.  I received it back with a new hammer. They found my hammer was a M16 hammer that was converted to use in an AR, but the person did a lousy job and it was not milled to work properly.  

I now keep a good supple of ejector springs and extractor springs and inserts on hand.  I also tried the Defender and keep some o-rings on hand.  You may want to consider keeping a spare ejector on hand as well.

Good Luck

Mike

Thanks..i will try the O-ring fix  and see if that corrects it. After doing some reading on the suggestions It looks like that should take care of it. I will definately look into the stiffer spring though aswell. Thanks for the insight..Most appreciated

Good reading if you have the time,
www.ar15.com/forums/topic.html?b=3&f=14&t=153425

Hi..I added the O-ring as mentioned and she runs perfect now. Thanks for the info guys