View Full Version : AR ejection issues?
SarcoBlaster
03-06-11, 04:56
I was at the range today with my AR and was having some issues that I've never had before. No changes were made from the last time it worked properly, so I'm not sure what the problem is. Anyway, throughout the day, I would get random failures to eject and in the pictures below, you can see what I mean.
The bolt has the black extractor insert and o-ring, the gas key screws are staked and aren't loose, and the gas rings are still good.
In the first two pics, the empty casing would stovepipe. I removed the magazine, pulled the charging handle back, and the casing would fall out. There was a live round partially in the chamber, but the base of the empty case kept the bolt from going into battery:
http://img.photobucket.com/albums/v96/SarcoBlaster/FTE1.jpg
http://img.photobucket.com/albums/v96/SarcoBlaster/FTE2.jpg
In the next two pics, the empty casing ended up getting caught on the front edge of the ejection port. You can see in the last picture that there is a live round that was just getting stripped from the magazine, but due to the position of the empty casing, the bolt couldn't move forward. When I locked the bolt back, the casing was still being held by the extractor with very light pressure, but fell out when I touched it.
http://img.photobucket.com/albums/v96/SarcoBlaster/FTE3.jpg
http://img.photobucket.com/albums/v96/SarcoBlaster/FTE4.jpg
It wasn't isolated to any one magazine and would happen randomly. However, the one thing that I did notice when I would get the failure to ejects was that the ejector was not all the way forward. I took the BCG out to examine it and when I used a bullet tip to press down on the ejector, it was very sluggish.
Once I got home, I put a drop or two of oil on the bolt face near the ejector and worked it a few times with a punch. Brass shavings were brought to the surface and now the ejector moves freely.
Finally, The bolt was clean before I used it today, so the problem didn't appear until my 5th or 6th magazine through the gun.
Based on all that info, would the most likely culprit be the ejector being clogged up by the brass shavings? I was shooting Privi Partisan 5.56 (the kind with the nasty red primer sealant) and brass shavings seem to be plentiful when using that particular ammo. Haven't tried any other ammo yet to see if I get brass shavings also.
Any help would be greatly appreciated.
Thanks!
I don't run O rings under the extractor, Just the heavy spring with the black bumper. I have actually seen this heavy extractor tension smear brass on the bolt face. which can also cause the brass shavings.
I have shot Prvi m193 quite abit. And had a noveske rifle just start having faluire to feeds after two days of shooting. The gun was lubed at the beginning of each day.
After the problem came up I cleaned the gun and found some shavings under my extractor. That was about it and haven't had a chance to shoot that gun since.
Make sure everything is cleaned and lube. Take out the o ring. and feed it some Federal m193. It should be fine.
Based on all that info, would the most likely culprit be the ejector being clogged up by the brass shavings?
Definitely looks like it. T-TACS suggestions looks spot on. Give it a go and see what happens. You may also want to go over your extractor and check if it has any isolated, increased wear marks. I had an extractor in the past that was a tad out of spec which caused it to dig into casings and generate shavings during extended use.
how many rounds through the weapon?
your conclusion sounds about right. could be you didn't get enough lube in there to begin with. add a little brass sand, and it shut itself down. the ejector spring is relatively tense, though... it's usually pretty hard to get them to bind up. if it happens again, you should probably go ahead and replace the ejector spring.
Robb Jensen
03-06-11, 08:09
Who assembled the gun?
What length, brand and gas length on the barrel?
What brand bolt carrier group?
If it was a gun I was working on, I would pull the ejector, scrub out the ejector channel, assemble with a new ejector spring, lube. If the extractor spring was even slightly suspect, I would drop in a proper new one (BCM, Wolff, SAW come to mind). Springs are inexpensive and don't last forever. As mentioned above, check the condition of the extractor as well.
SarcoBlaster
03-06-11, 13:20
Who assembled the gun?
It's a Stag upper. The only thing I changed out on it was the Troy rail.
What length, brand and gas length on the barrel?
16", Stag 1/9 twist, carbine length.
What brand bolt carrier group?
It's one of the FN contracted BCG's purchased from a vendor here a couple of years ago.
I ran a magazine of Federal XM193 through it after it started having the problems and it ran just fine. Probably a combination of several factors? I'll have to pull the ejector out as well to take a look inside.
Robb Jensen
03-06-11, 13:23
If you have an o-ring on the extractor this can cause stuff like this as it can allow the extractor to over power the ejector.
SarcoBlaster
03-06-11, 13:35
If it's something as simple as the o-ring, I'm going to be relieved. Will take it out and see what it does the next time I'm at the range.
I'll also pull the ejector to take a look in there. Any suggestions on how to put it back in? It looks like I'll need at least 3 hands to hold the ejector in and replace the tiny roll pin!
If it's something as simple as the o-ring, I'm going to be relieved. Will take it out and see what it does the next time I'm at the range.
I'll also pull the ejector to take a look in there. Any suggestions on how to put it back in? It looks like I'll need at least 3 hands to hold the ejector in and replace the tiny roll pin!
you'll need a tool. you can make 'em fairly easily, if you're handy
if you don't already have a puller, large C-clamp, or a vise, you're better off just buying an ejector removal tool... this is probably the cheapest one you'l find. http://www.brownells.com/1/1/48919-ar-15-m16-bolt-vise-ar-15-m16-bolt-vise-sinclair-international.html
it's cheaper than buying a new bolt, at least. and probably cheaper than having a smith do it.
SarcoBlaster
03-06-11, 15:08
Well, I pulled the ejector out and this is what I found :eek:
http://img.photobucket.com/albums/v96/SarcoBlaster/Ejector.jpg
When I tapped the roll pin out, I had my thumb over the face of the bolt so the ejector wouldn't launch into oblivion. Well, it didn't go anywhere at all due to all the crap in the ejector channel. :rolleyes: The thing stayed where it was even with the roll pin out.
It moves freely now after I cleaned it out and I'll see if the brass shavings return during my next range trip. I also removed the extractor o-ring to see if that might have been causing the brass shavings.
wow.. maybe it's just the photography, but i don't think i've ever seen chunks that big inside the ejector channel before. its usually just a clump of clay-like carbon and sandy debris. is it a pretty sloppy fit?
SarcoBlaster
03-06-11, 16:57
wow.. maybe it's just the photography, but i don't think i've ever seen chunks that big inside the ejector channel before. its usually just a clump of clay-like carbon and sandy debris. is it a pretty sloppy fit?
Yeah, sorry for the crappy photo; couldn't get good lighting. The fit of the ejector is pretty good as far as I can tell.
For shits and grins remove the O-ring.
SarcoBlaster
03-06-11, 20:30
For shits and grins remove the O-ring.
Done. Will try it out w/o the o-ring and see what it does.
Thanks for the suggestions, everybody!
Interesting that the Federal XM193 you shot functioned properly after you started having problems with the other ammo.
Cant help but feel like the o-ring shouldn't be the cause here. Removing it may remedy the problem but that doesn't mean it was the cause. Lots of people use extra powe springs and o-rings or the defender things. They are pretty uniformly recognized as a reliability enhancer.
I would be doing a very careful inspection of the guts of the weapon to see if there is a burr or sharp edge somewhere that is shaving brass. In particular look at the bolt and bolt face. For example, does the hole in the bolt face that the ejector passes through have a sharp edge? coiuld this or something similar be creating the brass shavings?
It's worth considering because heavy extractor tension is a generally good thing and should not be the cause of this problem. Not saying it couldn't be, just shouldn't be.
Adrock1
adrock1,
Let me explain why I made the suggestion. I assume that you are new to AR's or don't understand the cycle of operation.
It is entirely possible that by adding the O-ring that you have too much tension on the rim of the cartridge so when the ejector goes to kick it out, it is doing so at slower speed. It could also be holding the rim so tight that it doesn't eject at all (or properly).
Internet AR15 medicine is hard to diagnose on the net. But, one must start looking at the obvious which is usually things that have been added after the fact.
Now couple the O-ring with a potential weak or clogged ejector and now you have the issues occuring as the OP has described.
Cant help but feel like the o-ring shouldn't be the cause here. Removing it may remedy the problem but that doesn't mean it was the cause. Lots of people use extra powe springs and o-rings or the defender things. They are pretty uniformly recognized as a reliability enhancer.
I would be doing a very careful inspection of the guts of the weapon to see if there is a burr or sharp edge somewhere that is shaving brass. In particular look at the bolt and bolt face. For example, does the hole in the bolt face that the ejector passes through have a sharp edge? coiuld this or something similar be creating the brass shavings?
It's worth considering because heavy extractor tension is a generally good thing and should not be the cause of this problem. Not saying it couldn't be, just shouldn't be.
Adrock1
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