[Case Mouth]

hello,

I was at the range with my armalite ar-10 yesterday and had a misfeed (failure to fully eject, next round loaded half way into chamber with spent case pinned above fresh round). I shot around 10 more rounds and had a stuck case. The case came out easily enough with cleaning rod but the extractor had torn the rim off slighly and in a strange "v" pattern. Looked at the extractor and it seems to have a damaged "v" in the rim curve instead of a semicircle. I hope yall can see in the pics what I mean...
So I guess I need a new extractor but what could have caused this???

 

[Friday]

Forgive me for assuming...but I'm guessing since it's an AR10 there aren't a whole lot of rounds through it as 308's really aren't plinkers. I'm also assuming you've kept the rifle in a clean-ish condition, reducing resistance on the ejection process.
That leads me to believe that the extractor was not top-flight steel to begin with. Doesn't mean that Armalite knew so, just means that a fatigued extractor (from the start) made it into your rifle.
Combine that with perhaps a weak-ish extractor spring not allowing the extractor to 'fully function', and that would assist in allowing the extractor claw to get prematurely chewed up.
I've seen beat-up extractor claws more than once. The extractor has a helluva job to do and it's a tiny part without much mass. If all the planets aren't aligned when that part is manufactured, it's gonna let go.
I think you've answered your problem in that you need a new extractor. Lots of trick aftermarket choices, but my first idea would be to contact Armalite. Perhaps they'll say send us the BCG and they pop in a new extractor.

 

[Case Mouth]

I bought it used but all indications are a low round count, I have shot it about 200 rounds since getting it and have not had any trouble whatsoever until these last ten rounds. I clean after each session. I have been looking for a replacement but armalite is fresh out and I can't get a straight answer from the internets as to if any 308 ar extractor will work on the armalite, most upgrade options like the JP mention dpms or just 308 and I know a lot of the ar-10 parts are armalite only.
I may take your advise and try to talk to armalite though, just wanted to see if perhaps there was something that could cause an extractor claw to wear and/or break in the middle like that.

 

[J.Boyette]

Was the ammo factory new? Remanufactured or handloads?

The extractor looks like its the wrong case size in the bolt. It's like a 6.8 SPC size not a standard.

John

 

[Case Mouth]

Was the ammo factory new? Remanufactured or handloads?

The extractor looks like its the wrong case size in the bolt. It's like a 6.8 SPC size not a standard.

John

They were hand loads, but are you asking if I loaded the wrong caliber in the gun or if the extractor is not the right extractor for 308? the former is definitely not the case and the latter I find hard to believe since I fired 200 rounds through it thus far without issue.

 

[J.Boyette]

Again The extractor is wrong. It looks like a 6.8. Not a standard.

Second did you small base size the brass? If not this can be a leading issue as well.

You only need to small base size the brass once.

Lastly did you FL size all the brass before loading?

 

[Case Mouth]

So if it is a 6.8 extractor would it function for as long as it has with 308? The rifle is used so I suppose it's possible, how do you tell for sure?
I don't small base any of them and yes they were all full sized, it's the only 308 die that I own.
Thanks for the help!

 

[J.Boyette]

I am assuming it's a 6.8. Look at the radius of the bolt face and the radius of the extractor. It's two different sizes.

On the brass, looks like this?

John

 

[Case Mouth]

I put the brass in the bolt and it looked ok as far the radius then.
What am I looking at on that brass pic? Do you mean the sizing marks or the rim?.
Thanks!

 

[J.Boyette]

Brass,

The sizing lines should run the length of the case even past the case head, unlike the above pic.

The lines going around the body of the brass are chamber marks.

If you can see a heavy line at the case head you might need a small base die IF you are shooting 7.62mm brass in a .308win. IF you are shooting a .308win in a 7.62mm you would be fine. If you are shooting a .308win in a 308.win you should be fine as well.

Please post pictures of the damaged brass when you can.

 

[Case Mouth]

Actually shooting 7.62 in a 7.62
Here a couple of pics of you can tell anything by the iPad pics....

 

[Case Mouth]

You can kind of see how the extractor has cut two grooves when it ripped the rim

 

[J.Boyette]

Looks good. How much soot is on the shoulder?

John

 

[Case Mouth]

Fair amount of soot on shoulder but it's only been a hundred rounds or so since I cleaned the chamber good.

 

[J.Boyette]

16" barrel I assume?

John

 

[Case Mouth]

Yes, how did you know?

 

[J.Boyette]

Right hand of god here.

Get a new extractor ok then buy this.

http://www.davidtubb.com/carrierweight-ar15

John

 

[Friday]

Adding weight to the bolt and slowing it down....
What a clever idea...wonder why I don't think of such things?
Probably because it's a Physics thing and I suck at math.
Good call JB.

 

[J.Boyette]

Adding weight to the bolt and slowing it down....
What a clever idea...wonder why I don't think of such things?
Probably because it's a Physics thing and I suck at math.
Good call JB.

It'd the soot on the shoulder is why the weight will help. Think about it.

7.62x51mm is a medium pressure round. Most of these companies to include Armalite treat these rifles like a high pressure gun (AR15) and screw with the operating system and get it wrong all the time.

Continuity of parts trumps cycle rate.

 

[613jmm]

Was the ammo factory new? Remanufactured or handloads?

The extractor looks like its the wrong case size in the bolt. It's like a 6.8 SPC size not a standard.

John

All of extractors in my AR15s and AR10s look that way. What you are seeing is the difference between the circumference that encloses the case head, and the inner circumference of the rim, where the extractor grabs the case. That why is it smaller, it isn't because it is the wrong one. I think the apparently missing chip in that extractor makes it look worse than it really is.