AR not pulling shot cases out of barrel

[MagnoliaHunter]

My AR is not pulling the shot cases out of the barrel when fired. The action is coming back and then trying to load the next cartridge. It will cycle by hand and eject. If I put a few drops of oil in where the loaded cartridge would sit, it will work correctly for a few rounds and then go back to not extracting. It is leaving a pretty good mark on the rim? where it tried to catch the case and extract it. Any ideas? Any where around Jackson, MS to get it looked at?

thanks

[2damnold4this]

What type of AR is it? What ammunition are you using? What buffer are you running?

If it's over gassed a heavier buffer may slow it down so the pressure in the chamber can drop enough to extract. I'd also look at the extractor spring/o ring.

[stagpanther]

What do the rims of the cases look like--is the extractor tearing right off? My guess is your cartridge is not quite chambered quite right--leading to "stickiness" in the spent case preventing it from being extracted--especially if your bolt will still lock back on an emptied magazine.

My motto is "cases do not lie" and usually have tell-tale hints of what's going on. : ) I'm not an expert tho.

Pictures always help--ESP gunsmithing can be quite a challenge.

[O4L]

Dirty chamber?

[Technosavant]

Is the chamber chromed?
Is the chamber cleaned WELL?
Is the ammo brass case or steel?
Have you tried different kinds of ammo?

It could be an ammo issue- I had an AR that did not like steel cased ammo- they'd stick in the unchromed (unchromed chambers aren't quite as slick as chromed) chamber and it was also overgassed, so it would rip the rim right off.

If it's been well cleaned and it does it with different kinds of quality ammo, I'd consider making sure the extractor spring is good and strong, complete with an O-ring and insert... the extractor could be slipping off the rim.

[Mobuck]

"If I put a few drops of oil in where the loaded cartridge would sit,"
I'd suggest you stop doing that. Oiling cartridges or the chamber is generally a NO-NO.

Otherwise not enough specific information to make even a good guess.

[HiBC]

Hot loads will do that.Actually,its better to say high pressure can do that.Brass that is too long can lead to high pressure with an otherwise OK load,for example.
What ammo are you shooting?
What AR? There are a lot of variants,each had lessons to learn.
Barrel length? gas system length? Which Buffer?

The extractor might need a little attention.The spring can get weak.There are O-rings and other rubber assists that do help the carbines.

Extractor could be worn/damaged or gunky.

[pete2]

Sounds like some of the rifles we took to Vietnam, single shot, had to punch the fired case out with a cleaning rod. I had a very disturbing when I took a buddies rifle on a scout. Got back to the track he said it's always been that way. Dumb flower child from San Antonio. Got it replaced when we got back to base. Never trust anyone.

[Bartholomew Roberts]

The rifle is trying to extract the cartridge too early while the brass is still blown out against the chamber wall. The brass is effectively "stuck" when the extractor starts pulling and it slips off the rim.

The two easiest fixes are:

1) Increase your buffer weight to slow down cyclic time and give the brass more time to pull back from the chamber.

2) Add an O-ring and a heavy-duty M4 type extractor spring to help keep the extractor from lifting off the rim.

They are dirt cheap and easy to do. Giving the chamber a good cleaning won't hurt anything either. The problem is occasionally even caused by match chambers being cut too tight to allow for much heat in the rifle.

[dakota.potts]

What do the stuck cases look like when you do get them out? Any shiny spots, dings, long scratches, etc?

[bamaranger]

There's always one guy in the crowd....this time it's me.

Typically, we refer to a cartridge that has been shot as "spent". The spent case is then extracted (pulled) from the "chamber", after the bullet has started down the barrel. Sorry, couldn't resist.

I'd REALLY clean the chamber, and I'd look as best as possible for pitting or deformity. I'd really clean the extractor hook (lots of shooters do not dismount this part for cleaning). I'd inspect the hook for obvious deformity by comparing to another, and replace if chipped. I'd test fire with brass case, quality ammo. If failure persists, I'd install a HD extractor spring, black damper and test again. If failure persists, I would replace extractor, even if it looked OK on inspection. If failure persists, I then would consider chamber dimensions and buffer issue.

[MagnoliaHunter]

I was going to try to shoot a couple this weekend to have pics to show. I will try to do it this weekend. it is gouging the rim. there are shiny spots and long scratches on the case. This is with factory ammo. The last was Remington, I think. It has done it with several different brands. I will check when I get home to be sure. I have cleaned it several times. Even had a ex military buddy go over it to make sure it was cleaned. he took everything apart and cleaned it but said that it looked good. Its a Rock Island Armory. It has not always done this. Sorry but I have no idea what the buffer is.

[stagpanther]

If your rim is being gouged--assuming the cartridge freely chambers to begin with--then what Bart says sounds more likely--your brass hasn't "snapped back" enough from expansion before your bolt tries to strip it from the chamber would be my guess--BUT it's also possible--based on scratches along the case that it's having difficulty feeding and chambering as well--which can cause it's own issues. If it were me, I would make a dummy round (no powder DO NOT USE A LIVE ROUND UNLESS YOU POINT THE WEAPON AT SOMETHING YOU DON"T MIND DESTROYING AND THEN DISCARD THE LIVE ROUND) or get a buddy to do one for you, stick it in the mag, drop the bolt and see if you have any problems ejecting it by hand. If there is a lot of resistance and the cartridge comes out notable dinged up--then I would say you might have a feed issue. Just armchair guesses. : )

[marine6680]

Ok... how many rounds through the rifle?

It sounds like an over gassing issue or a damaged extractor or weak/broken extractor spring... So the bolt is trying to move rearward and extract the brass too quickly, so the pressures are still too high... or the extractor is slipping on it's own due to low gripping strength.

First thing I would do is replace the extractor, you can get an extractor kit pretty cheap. (If the rifle is fairly new, it may not be an extractor issue, but it does not hurt to check)


The buffer is the part that sits inside the buffer tube with the main spring...

It looks like this


It is located here


A buffer has weights inside and works similarly to a dead blow hammer, to prevent bolt bounce. They make them with different weights, they are labeled accordingly... if the face is blank, it is the standard and lightest type, if it has an "H" it is the next heavy, then there is "H2" and "H3" which increase weight accordingly.

It also affects the cyclic rate and timing of the system during firing. The blank standard buffer is no longer used for mil spec rifles, and is really only kept around as a cost cutting measure by some manufacturers, as they cost less to make...

The "H" is the standard buffer weight now, with H2 often being recommended for over gassed rifles or as the default for most manufacturers rifles that use a carbine length gas tube with a 16in barrel.

[O4L]

Hope you get it working. Heck I didn't know RIA made AR rifles.

[Mobuck]

You won't get the chamber clean using bore sized patches. Sacrifice a 9mm bore brush or get an actual .223 chamber brush and scrub the heck out of the chamber. I'd use an old 9mm brush on a section of jointed cleaning rod and a rotary motion(honestly, I use a cordless drill if it's really that bad) with copious amounts of whatever solution you desire. Follow up by wrapping a patch around the already buggered brush to get the crud out and then clean the bore again to remove anything you may have pushed into the chamber neck area.

[MagnoliaHunter]

I used the 223 chamber brush when cleaning. I thought about using a cordless drill but thought it might be too much.

The gun has had maybe 400 rounds through it.

I will look at the buffer to see what weight is in it.

I will try what StagPanther suggested.


I will definitely get some pictures of the cases this weekend for you guys to look at. Until then thanks for the help.

[precision_shooter]

My vote is on an extremely dirty chamber. Clean it and all should be well.

[Bartholomew Roberts]

The gun has had maybe 400 rounds through it.

What brands and types of ammo?
Is the same brand and type of ammo that worked before causing problems now?
What was the last ammo that worked and the first ammo that showed this problem?

[2damnold4this]

Its a Rock Island Armory.

Could it be a Rock River Arms carbine?

My Rock River carbine has a .223 Wylde chamber that is a bit tighter than a 5.56 chamber. It also has a carbine length gas system on a 16 inch barrel and is way over gassed. It's accurate but an H2 buffer helped it a bunch with cycling.

[Slamfire]

I was going to try to shoot a couple this weekend to have pics to show. I will try to do it this weekend. it is gouging the rim. there are shiny spots and long scratches on the case. This is with factory ammo. The last was Remington, I think. It has done it with several different brands. I will check when I get home to be sure. I have cleaned it several times. Even had a ex military buddy go over it to make sure it was cleaned. he took everything apart and cleaned it but said that it looked good. Its a Rock Island Armory. It has not always done this. Sorry but I have no idea what the buffer is.

I would call RIA and tell them your problem. I have a couple of RIA AR15's and they are quality rifles.

What I suspect is a tight barrel raising pressures. At unlock, the bolt opens up when there is still pressure in the barrel, around 650 psia or less, and if the pressure is too high, the case is not coming out.

This is from Chinn's book of the Machine Gun Vol IV, free to download at:
http://www.ibiblio.org/hyperwar/USN/ref/MG/








When the first M16's were issued in Vietnam, the powder the cartridges were using was a ball powder developed for the M14. Pressures at unlock were too high and many a good American boy died with a jammed M16 in his hands. Colt, the manufacturer, advised Troopers to oil their cases, to break the friction between case and chamber. This was unreliable, it did improve extraction, but, it is not a cure for the ill of overpressure ammunition. Because steel case ammunition is so troublesome in AR's, I regularly oil my steel case ammunition. I put a couple of drops of oil on a stack, roll them around, load them. Very messy. If pressures at unlock are OK, then what I am doing aids in the extraction of the round. But, case lubrication will not solve what is essentially an over pressure situation.


It is positively amazing the ignorance of the shooting community towards the function and history of automatic weapons. Even though Chinn's series is free to download, few read the books. Few read books anymore anyway. There were a number of weapons that required oilers to function. They have been out of inventory for so long that shooters have lost the memory of them, and few people can afford one anyway. This is an example of one:


Type 92 Japanese Machine gun, oiler function minute 14

http://www.forgottenweapons.com/type...james-d-julia/

These are cartridges used for the 276 Pedersen rifle, instead of oiled cases, the cases were covered in wax. At the temperatures of combustion, the wax turned into a liquid in the chamber, and broke the friction between case and chamber.



I believe you have a tight barrel and if RIA won't fix the thing, then you have a rifle that can only be used with reloaded ammunition. My Kreiger barreled match rifles all have tight barrels and I have to cut my 223 loads. Loads that function fine in a Wilson match barrel, I have to cut them by 1.5 to 2.5 grains for the Kreiger barrels. Don't do anything drastic like reaming out the chamber.

[Mobuck]

"There were a number of weapons that required oilers to function."

There is a BIG diff between a cycling mechanism that was designed(or re-designed) to use lubricated case ammo and oiling cases for use in designs not intended to use oiled cases.
The fact that you HAVE done so has absolutely zero bearing on the safety of doing so.

[bamaranger]

Have you pulled the extractor and inspected same? Is the exractor spring seated correctly, and is the damper present? A spring and damper are cheap, and a new extractor is about $20.00. As noted, I'd begin there if the chamber seems OK.

Long scratches on the cases are likely from feed lips on the magazines, I would not worry about that too much....pretty common.

[Slamfire]

There is a BIG diff between a cycling mechanism that was designed(or re-designed) to use lubricated case ammo and oiling cases for use in designs not intended to use oiled cases.
The fact that you HAVE done so has absolutely zero bearing on the safety of doing so.

Designed? Why don't you tell me how locking mechanisms are designed. I will help here, it all comes down to load, that is foot lbs of force. Assume a similar cartridge, any cartridge, what is the difference in load carrying capability of a mechanism that used oilers or greased rounds, and one that does not?

[ed308]

You Rock Island AR wouldn't be a 6.8 would it? If so, Remington ammo is underpowered and has a reputation for causing problems with 6.8 ARs. I would inspect the ejector, ejector spring and gas block (make sure it hasn't shifted). If still having problems, try polishing the chamber with JB Bore Paste and Kroil. Brownell's sells both plus the pads to polish the chamber.

http://shop.brownells.com/gun-cleani...FcW2wAod4FMHfg