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Discussion Starter · #1 ·
I've had issues with the extractor not having enough force to fully extract the spent round from the chamber with my 6.8. Already changed to a Colt Gold extractor spring and it was better, but still had some FTE last time out. Part I don't like most is when it screws up brass to where it can't be reloaded.

Wondering how many others have this issue with their 6.8 and if it makes sense to just buy a LMT bolt head with enhanced extractor and double springs.
Not sure if the 6.8 just requires more lock time for the case to contract or just more ejector force to hold on to the case. Thinking about an adjustable gas block as an alternative to the LMT bolt.

The upper and BCG is from PSA. Already checked for gas leaks and barrel port alignment to gas block... all good there.

Experience in the matter is appreciated...
 

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I've had issues with the extractor not having enough force to fully extract the spent round from the chamber with my 6.8. Already changed to a Colt Gold extractor spring and it was better, but still had some FTE last time out. Part I don't like most is when it screws up brass to where it can't be reloaded.

Wondering how many others have this issue with their 6.8 and if it makes sense to just buy a LMT bolt head with enhanced extractor and double springs.
Not sure if the 6.8 just requires more lock time for the case to contract or just more ejector force to hold on to the case. Thinking about an adjustable gas block as an alternative to the LMT bolt.

The upper and BCG is from PSA. Already checked for gas leaks and barrel port alignment to gas block... all good there.

Experience in the matter is appreciated...
Is the extractor spring missing the enhancer (o ring). I've never had problems, except once, easily solved, like you describe with any of my 6.8's and I've had 5 of them over the last 3-4 years. A couple with enhanced bolts but most with the cheapest AIM, PSA or other bolts. I've also never had to use an adjustable gas block on any of my 6.8's and I'm not certain it will solve your problem. It's probably money wasted. You have another underlying problem you need to solve. I don't think a different bolt is going to solve it. Any standard bolt should work fine unless 1) The extractor enhancer was omitted when the bolt was assembled (either an O Ring around or rubber insert inside the spring. 2) Your chamber is contaminated and causing the rounds to hang in the chamber (sometimes simple cleaning isn't enough to remover build up causing the brass to stick in the chamber when the rifle is fired). I had one develop the problem you describe right away and I had to polish the chamber. Once I did that, the problem never resurfaced. I've heard of cases where a Melonite chamber had some debris from the process left in the chamber that had to be lightly polished out with Bore Paste and a tight patch.

One question. Reloads or factory ammo? Are you loading too hot? Any pressure signs, just FTE?
 

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I had a similar issue along with failure to lock back, was cured by polishing the chamber. Took 10 minutes and used stuff already in my shop (i.e. no cost). Brass will look frosted or weathered after firing from a rough chamber. I do use a LMT enhanced bolt, but it was there from the start. My dad's 6.8 uses a standard style bolt and has no troubles.

-Alexander
 

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Discussion Starter · #4 ·
Thanks for the replies. I haven't tried polishing the chamber yet, but it sounds like the next logical step. It has a chrome lined barrel.

Been using Hornady factory loads.
 

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As mentioned;

Polish the chamber and see if that doesn't solve your problem, but don't over do it.

Extractor springs should include the rubber bumper, you can also add an o-ring to increase the grip strength of the extractor.


Sent from a final firing position, the crosshairs are on you!
 

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Sounds like you have a timing issue vs weak extractor spring. Which gas system is on the barrel? Carbine or Midlength? What Buffer weight? If you're using a Carbine Buffer you might try a heavier one, H1 or H2 and see if that helps. That will slow down the extraction process to allow time for the chamber pressure to decrease before the extraction process begins.

Too strong an extractor spring in trying to extract too early is only going to rip the case rim which what I guess it what you're seeing.

And of course ensuring the chamber is clean.
 

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I've had issues with the extractor not having enough force to fully extract the spent round from the chamber with my 6.8. Already changed to a Colt Gold extractor spring and it was better, but still had some FTE last time out. Part I don't like most is when it screws up brass to where it can't be reloaded.

Wondering how many others have this issue with their 6.8 and if it makes sense to just buy a LMT bolt head with enhanced extractor and double springs.
Not sure if the 6.8 just requires more lock time for the case to contract or just more ejector force to hold on to the case. Thinking about an adjustable gas block as an alternative to the LMT bolt.

The upper and BCG is from PSA. Already checked for gas leaks and barrel port alignment to gas block... all good there.

Experience in the matter is appreciated...
Not extract fully from the chamber? As in the extractor is slipping off the rim and damaging the rim of the case? Or the extractor is not slipping off the rim but there is not enough force(gas pressure) to remove the cartridge from the chamber? If the later it is not a extractor problem but a gas problem.
 

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just wondering is the case stove piping? or is the extractor coming off the case prior to that? if you could get a picture of the malfunction and post it that might help as well.
 

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A little more info as H suggested would be helpful.

A sticky chamber can cause your issues try that first.


With a good extractor and spring;
Fail to extract is either from too much or too little movement of the bolt carrier group. Too much can be identified by harsh recoil and bent case rims.

Too little gas would be identified by short stroking.


Sent from a final firing position, the crosshairs are on you!
 

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To polish the chamber I took a 1/4" brass rod about 14" long, cut a slit about 1" deep and 1/8" or so wide in one end. Take a strip of the red scotch Brite pad about 3" long and 1" wide, slip the middle of it in the rod, Chuck the rod in your drill and run it at medium speed while moving it in and out for about a minute then check. Follow up with #0000 steel wool or a rag and JB bore paste for a minute or less. Careful not to jam it too far into the chamber. Clean and inspect. Repeat if needed, but it should have a nice medium bright satin finish look, not enough to fully mirror polish it.


-Alexander
 

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To polish the chamber I took a 1/4" brass rod about 14" long, cut a slit about 1" deep and 1/8" or so wide in one end. Take a strip of the red scotch Brite pad about 3" long and 1" wide, slip the middle of it in the rod, Chuck the rod in your drill and run it at medium speed while moving it in and out for about a minute then check. Follow up with #0000 steel wool or a rag and JB bore paste for a minute or less. Careful not to jam it too far into the chamber. Clean and inspect. Repeat if needed, but it should have a nice medium bright satin finish look, not enough to fully mirror polish it.

-Alexander
Don't use the ScotchBrite or steel wool if your chamber is Melonite.
 

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Don't use the ScotchBrite or steel wool if your chamber is Melonite.
The OP states in post#4 that his barrel is chrome lined, so it's doubtful that his chamber is melonited. Not saying it's impossible, just..unlikely.
 

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Discussion Starter · #13 ·
Thanks for the replies.

The first round will get extracted from the chamber but not eject and the next round will be stripped from the mag and double stacking occurs in the chamber. I haven't noticed damage to the case rim, just the mouth of the case gets crumbled when the bolt jams the empty case forward.

Mid-length gas on a 14.5" barrel.

I've cleaned the heck out of the chamber, stripped the chrome BCG/cleaned/oiled and hand cycled numerous times. Just checked and it doesn't have an o-ring on the extractor. Perhaps that should be the next step. Thought the Colt gold would provide enough force, but guess not. This is my first 6.8.
 

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Thanks for the replies.

The first round will get extracted from the chamber but not eject and the next round will be stripped from the mag and double stacking occurs in the chamber. I haven't noticed damage to the case rim, just the mouth of the case gets crumbled when the bolt jams the empty case forward.

Mid-length gas on a 14.5" barrel.

I've cleaned the heck out of the chamber, stripped the chrome BCG/cleaned/oiled and hand cycled numerous times. Just checked and it doesn't have an o-ring on the extractor. Perhaps that should be the next step. Thought the Colt gold would provide enough force, but guess not. This is my first 6.8.
This is a completely different issue than your 1st post where you stated the extractor didn't have enough force to extract the spent case from the chamber.

Appears you have an ejection issue.

Take out your BCG and check the ejector. Depress the ejector to see if it is stiff but moves freely or sticking.

1. Place a single round in a magazine, load it and charge the rifle, then fire it.

2. After firing the single round what happens with the spent brass? Does it extract from the chamber and eject, or does it extract and end up left in the chamber or stove piped?
Does the BCG lock back or ride the empty case forward?

You may have a weak ejector spring.
 

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...

You may have a weak ejector spring.
Did it ever eject correctly?

If it did then there is also the possibility of brass flakes/shavings jamming the ejector or even a broken ejector spring.
 

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Don't use the ScotchBrite or steel wool if your chamber is Melonite.
Yes, good advise

The OP states in post#4 that his barrel is chrome lined, so it's doubtful that his chamber is melonited. Not saying it's impossible, just..unlikely.
^^ this is why I posted the method I used on my SS barrel.

-Alexander
 

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Thanks for thdifferent. first round will get extracted from the chamber but not eject and the next round will be stripped from the mag and double stacking occurs in the chamber. I haven't noticed damage to the case rim, just the mouth of the case gets crumbled when the bolt jams the empty case forward.

Mid-length gas on a 14.5" barrel.

I've cleaned the heck out of the chamber, stripped the chrome BCG/cleaned/oiled and hand cycled numerous times. Just checked and it doesn't have an o-ring on the extractor. Perhaps that should be the next step. Thought the Colt gold would provide enough force, but guess not. This is my first 6.8.
Before, you described a completely different problem. You'll have to make up your mind what the real issues really are or everyone will be chasing their tails trying to help. Now you have extraction, feed, ejection and God knows what other problems. Now, the possible solutions are becoming a very long list.....or, again, one solved by chamber polishing alone. A contaminated chamber will hang rounds extracting AND slow down and restrict ejection by slowing or shortening the bolt stroke during any actual extraction that actually happens. Of course there are about 5 more things that could be happening too with your expanded list of issues.
 

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Discussion Starter · #18 · (Edited)
The extractor doesn't hold the case rim long enough for the case mouth to clear the chamber port to eject and the case is dropped in the chamber. The bolt continues back and strips another round and causes a double stack. I haven't had this issue with other caliber AR's and thought it might be more common with the 6.8.

Polishing the chamber sounds like a good idea to remove any roughness in the chamber that could hinder case extraction. Adding an O-ring under the extractor can't hurt either. Just ordered a few. I'll also check the condition of the extractor to see if its sharp.

I think I have a plan forward now. Thanks for the replies!
 

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The extractor doesn't hold the case rim long enough for the case mouth to clear the chamber port to eject and the case is dropped in the chamber. The bolt continues back and strips another round and causes a double stack. I haven't had this issue with other caliber AR's and thought it might be more common with the 6.8.

Polishing the chamber sounds like a good idea to remove any roughness in the chamber that could hinder case extraction. Adding an O-ring under the extractor can't hurt either. Just ordered a few. I'll also check the condition of the extractor to see if its sharp.

I think I have a plan forward now. Thanks for the replies!
I think your bolt speed is too slow or being delayed causing the case dump. After about 400 rounds, when shooting squirrels, I start having that problem when the rifle and chamber gets good and dirty. It takes about 700 in my 223's
 

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As described above you should be checking the ejector to ensure its working. Shaved brass can get in it and cause it to not move properly. Also check the angle on the extractor to ensure that it isn't broken, rounded or at to large an angle.

Chamber polishing doesn't sound like the issue


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