I built a 9mm ar.
standard lower and upper, with a spikes magblock. built in ejector and lrbho.
nitride 8 inch barrel. Colt mags and glock cut bolt.

I toke the magblock apart and straightened out the ejector. Because before I could barely get through a mag without the spent shell sticking.

Now I can get through a few mags, but periodically it will do it again.
The spent shell has left the bolt, but it is spun around backwards but doesn't leave the gun. The new round is starting to chamber. the spent case is above and behind the new round being chambered.

Is there some other tweak?

4 different mags, asc, and 2 different types of ammo.

Thanks. I did that originally before I straighted it out.
I forgot to check it again after.
I thought it was more adjustible. That the hold down was slotted, but turned out not to be. I guess me and the last owner bent it up a lot trying to make it work and must have just not quite got there.

So I took a closer look at it, and it appears to be flat and lined up fine.
https://imgur.com/JefPgJV

I took another look at the bolt.
The extractor doesn't actually come out far enough to hook over the rim of the case.
It puts tension on it, but just barely. it just touches it.

I am guessing this might be my problem.
But it doesn't seem adjustable. It is pinned in and it is a pin size slot.

are there different sizes for extractors? do I just slot it bigger with a file?
ugh, I just realized, I can file the hook bigger so it allows the case to fit under it.

or am I barking up the wrong tree?

A friend of mine had what sounds like a similar issue. A case would extract and then end up lodging in the upper/bolt while the bolt was starting to load the next round.  Ultimately it turned out that his plastic 9mm case deflector was bouncing the round back into the ejection port.  He took the 9mm case deflector off and the gun has run perfect since.
Hopefully this helps

That is odd.  Is he using a 9mm buffer or a standard?  That almost seems like the bolt is traveling backwards to fast and to deep, stopping the case from being ejected. The casing should be on its way out before the plastic shell deflector is in the way.

By the way, if it is the plastic insert that goes with the shortened port door, that is a gas deflector.

It is using a 9mm buffer, and yes the deflector that went with the half door.  I cough it on slow mo camera (cell phones are great) and you could see it eject and bounce off the deflector and right back into the action.  Removed the deflector, put on a full port door, and all issues went away.

https://imgur.com/EOBBZLB

seems to look ok to me.
I got a spikes bolt, but the extractors don't seem to interchange.

I can put the spikes extractor into this no namer bolt, but not the other way around.
The spikes is even shorter so a rim doesn't even come close to going under the hook.
But in the spikes bolt it fully covers the rim.

I filed some of the hook away and now this one covers the rim better. I can no longer just pull the case straight out. where I could before.

unfortunately the place I got this bolt from is gone out of business. So if it does break an extractor, I don't know where to get it from.

The spikes bolt is dragging or something and it won't close fully with a mag inserted. I think I would have to move the block down to make the spikes bolt work at all.
I hope the hook was the issue with this bolt.
Worst case I guess I start all the adjustments again with the spikes bolt and see if it runs.

I am interested in the idea of it bouncing back in, and that might explain the randomness of it. But I will give the hook fix a try first.
It will probably be a month at least before I get to try it again.

It looks like a 1911 extractor. There are a ton of them available out there. Might have to do a little fitting.

I got it from www.armil-spec.com

here is a side pic
https://imgur.com/a/r4K6QRt

it is an odd one because it only has 1 bolt holding the fake gas key on.

https://imgur.com/a/Wy7US5z

Thanks, any luck on what extractor it is?

thanks.
Just let me know when I can order them from you.

Just wanted to update. Got a chance to go to the range today.
filing the extractor was the ticket. only had one issue, after the first round but I think I loaded too many in the mag.

Rudy, just let me know when you get those extractors so I can buy a couple off of you.

Good info!

Adding this, and Rudy's suggesion about having a flat face ejector tip, to the Lots of 9mm AR information thread for future builders' reference.

I am not sure that is true.

I have this as a spare bolt.
https://imgur.com/a/PSXsz0O

https://imgur.com/hMaSPaB

I got it used with no markings.

I think it is cmmg. but could be wrong.
I tried to swap the extractor from it.
while it did fit, it was short. It was so close to the bolt face I couldn't cut enough off of it to make a shell fit under it if I wanted to.

if it isn't cmmg, please let me know.