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Jdurzua
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Posted: 7/2/2012 7:38:20 PM
A couple of days ago I took my AR to my buddies and was having a stove pipe issue. The gun is a factory built Oympic the only modification I have made was a timney trigger. The gun has never had any issues before now. While I had some friends there they noticed that I had gas escaping from the front site. The ejected rounds were just falling out it even looked like some were going up and hitting the front rail. I took the gun down and just replaced the gas tube and cleaned everything. I took the gun back out last night and didn't notice any gas coming out from the sight. But the gun seemed to do it still I did notice that this time it would do it on the 3rd to last casing. When it stove pipes it does have a new round in the chamber to. The gun has never short stroked or not locked back on empty mag. I did notice that when you pull the charge handle back all the way that it does go flush if not farther down than the ejector opening. The buffer and spring are all Original as well as the tube. This gun has had between 2,000 and 3,000 rds fired through it. I really don't want to have to send the gun back to olympic but will if need be.


Thanks
Jonathan
AlphaThree
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Posted: 7/2/2012 7:49:04 PM
Maybe an extractor problem. Purchase an upgrade kit. If that is it, it's a $5 fix.

http://www.laruetactical.com/extractor-upgrade-kitar-15mil-specextra-power-5-coil-extractor-spring-extractor-insert-and-viton-o-r
Eric
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Posted: 7/2/2012 7:54:52 PM
It sounds like you're experiencing a failure to eject. I would detail strip and clean the bolt, to include removing the ejector and ejector spring. Ensure that the ejector channel is free of gunk/debris. Drop in a new ejector spring since you have it disassembled. While you're at it, ensure that the extractor spring has good tension and when in doubt, drop in a new one. Oly Arms is unusual in that they don't use an extractor spring insert, but I would drop one in as well. Shown is the current Colt extractor spring with proper black insert.
Obo2
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Posted: 7/2/2012 8:06:27 PM
check your ejector should move freely and be nice and springy.

make sure your extractor is in good shape as well.

Next Pull your charging handle all the way back does your bolt retract past the ejection port?

It should still be visible approx. 1/4"

your problem is most likely caused by too much rearward travel.

most recent http://www.ar15.com/forums/t_3_66/577737_.html&page=1&anc=bottom#bottom

first threadhttp://www.ar15.com/archive/topic.html?b=3&f=66&t=559790

my reply in the most recent

there are a couple ways to remedy this problem then,

a new spring could work but probably won't

the correct way is to lap down the receiver extension so you can screw it in further this would require removing it and then grinding cutting or filing it down then re-installing. or i guess you could try a different receiver extension.

I was able to solve mine by swapping bolt carriers between rifles.

The easiest least expensive way is to add some spacers under your buffer spring, pull your buffer and spring out and get some delrin washers(best choice), regular washers or even some quarters that just fit the inner diameter of the buffer tube put in as many as you need so when you pull the charging handle back all the way the bolt still shows in the ejection port ~1/4"

Many people are adverse to putting quarters in their rifle and if you are I would recommend you at least try it first as a trouble shooting step if it fixes the problem you can go the more permanent correct route.

The spacers will be retained by the buffer and spring so there is no need to be concerned with it causing a malfunction.
007Kevin
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Posted: 7/2/2012 8:40:05 PM
[Last Edit: 7/2/2012 8:42:24 PM by 007Kevin]
Wouldn't shimming the buffer tube just be a band-aid to the problem? ETA - or swapping parts or serious gunsmithing?

The rifle worked fine before for a number of rounds and now it does not. Wouldn't something wearing out be suspect? Just trying to learn.
Jdurzua
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Posted: 7/2/2012 9:27:33 PM
My model just has the spring and O-ring on the end. The bolt carrier is flush or counter sunk in the ejector window. But Im pretty sure that it aways has been. I did install new buffer and spring and the bolt still goes back to far so I didn't purchase the parts. I think that I am starting to lean towards a ejector or extractor problem. I think that I am going to order some new springs. A guy I know that is very good at building AR's says that the bolt moving back beyond the window shouldn't cause the problem because as soon as the casing comes out of the chamber the ejector should start to push it out. I will take a couple Quaters with me next time I take it out to try but that does seem like a band aid.
Obo2
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Posted: 7/2/2012 10:05:10 PM
[Last Edit: 7/2/2012 10:09:11 PM by Obo2]
the shims are ultimately a band aid but a good diagnostic tool and ultimately would cause no issues as a long term fix.

when the bolt goes back too far the case will bounce off the rear of the ejection port and then dance in the receiver and just sort of fall out or fly forward and hit the rail or your support hand or stovepipe as you have described.

The case does start pivoting out as soon as it clears the barrel extension but doesn't really eject until the bolt stops traveling rearward.

I did miss that it's ran fine for a couple thousand rounds so new springs in your ejector may fix it.

Jdurzua
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Posted: 7/2/2012 10:12:47 PM
I think that I am about to order that kit from larue tactical. I am probably going to order there mil spec tube kit as well. That should fix the bolt going to far back. I am 90% sure that my tube and CTR are Mil spec because the back of the tube is flat. Im assuming that all flat back tube are milspec?
Obo2
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Posted: 7/2/2012 10:29:45 PM
all milspec tubes are flat backed but not all flat backed tubes are milspec.

commercial can basically be whatever the heck it wants but typically your assumption is correct
Eric
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Posted: 7/2/2012 10:38:29 PM
If it is a stock OA carbine, you have a commercial receiver extension (buffer tube).
007Kevin
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Posted: 7/2/2012 11:04:33 PM
Originally Posted By Jdurzua:
... I am probably going to order there mil spec tube kit as well. That should fix the bolt going to far back. I am 90% sure that my tube and CTR are Mil spec because the back of the tube is flat. Im assuming that all flat back tube are milspec?


This didn't make sense. The tube kit wouldn't change anything. I would leave it alone till it breaks.
Obo2
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Posted: 7/2/2012 11:06:45 PM
Originally Posted By 007Kevin:
Originally Posted By Jdurzua:
... I am probably going to order there mil spec tube kit as well. That should fix the bolt going to far back. I am 90% sure that my tube and CTR are Mil spec because the back of the tube is flat. Im assuming that all flat back tube are milspec?


This didn't make sense. The tube kit wouldn't change anything. I would leave it alone till it breaks.


i different tube could screw in further solving the issue of too much rearward bolt travel... probably won't though
Jdurzua
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Posted: 7/3/2012 12:41:02 AM
That's what i don't understand why would the bolt all the sudden start going to far back. Even when I dropped in a new buffer and spring. Is there something that could be damaged inside the tube. I want to fixThe rifle correctly not a band aid.
Obo2
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Posted: 7/3/2012 1:01:07 AM
Your bolt was probably always able to travel back too far while it was new the spring had enough tension and the bcg upper were still mating providing a bit more friction to slow it down.

The shims are a band aid replacing or smithing parts is not.

You may also have luck just trying a heavier buffer
Jdurzua
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Posted: 7/3/2012 1:06:14 AM
Well from what I'm reading I should be able to put the larue tactical tune and buffer assembly on and be done with it. Plus I would have some wonderful dillo dust.
Obo2
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Posted: 7/3/2012 1:11:30 AM
[Last Edit: 7/3/2012 1:14:37 AM by Obo2]
their dillo dust is tasty and i try to squeeze their tactical beverage entry device in to most of my gun pics.

love their index clips too

not seeing the product you are referring to can you post a link?
Jdurzua
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Posted: 7/3/2012 9:41:42 AM
Here you go.
http://www.laruetactical.com/mil-spec-receiver-extension-kit
muldoon
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Posted: 7/3/2012 10:43:27 AM
your buffer spring is sacked.
The carrier is rebounding violently off the back of the tube.

Tubb spring is good.
Jdurzua
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Posted: 7/3/2012 11:32:37 AM
I would agree that it is rebounding off the tube. So should I just throw a new buffer and spring in and see what happens, or just replace the whole tube and all?
muldoon
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Posted: 7/3/2012 11:58:13 AM
[Last Edit: 7/3/2012 12:00:17 PM by muldoon]
I would say, a new spring, only, provided...............

Tube is ok if dimensions are cool.
buffer is ok if weights rattle inside.
get a known good one. from David Tubb !
The $5 springs they give us are only good for a very short ( 5k ) amount of cycles.

as an aside.
a good carrier weight never hurt my 10 different ar15's I have owned.

M
Jdurzua
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Posted: 7/3/2012 5:08:20 PM
Well I got me a new spring today from the local shop I will try to run it through its paces tonight and see what is going on. I can diffenatly see the bolt carrier is hitting the lower reciever.
Dano523
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Posted: 7/3/2012 6:12:34 PM
[Last Edit: 7/3/2012 6:15:26 PM by Dano523]
As stated, if the bolt will lock back on the last round out of the mag fired, then the stroke is fine.


Pull all the way back on the charging handle, and confirm that the face of the bolt stops in front of the ejection port window rear edge (1/4" to 3/8" is ideal). If the face of the bolt is flush with the window, then as the buffer bumper goes to compress under normal recoil, then it's going to be behind the back of the ejection window at recoil, with the spent case bounced off the back of the ejection port window, and back into the action.

Washers are a good temp band-aid to trouble shoot, then the ideal solution is to pull the receiver extension, and shorten the end of the tube a few winds so it re-indexes everything correctly again (butt stock index/buffer retaining pin retention), while at the same time, stops the face of the bolt short of the back edge of the ejection window.


And why is the problem now happening,

As stated, could have been a new spring that temp band-aided the problem, or just the buffer bumper is now softer/slightly compressed shorter, and now allowing such.

Bottom line, if you take a look at the spent case that is stove piped, you going to see a nice smile face dent in the case just short of the rim section. That is where is tagged the ejection port window on the way out, and cause it to be deflected back into the action. Stop the spent casing from tagging the back of the ejection port window (bolt stopping in front of the port window) and you will have solved the problem.

To add: Obo2 had you dialed in way back on the solution, and why you did not listen to him is beyond all of us.
Posted By PlaymoreMinds:

'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...

<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
Jdurzua
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Posted: 7/3/2012 8:07:58 PM
Originally Posted By Dano523:
As stated, if the bolt will lock back on the last round out of the mag fired, then the stroke is fine.


Pull all the way back on the charging handle, and confirm that the face of the bolt stops in front of the ejection port window rear edge (1/4" to 3/8" is ideal). If the face of the bolt is flush with the window, then as the buffer bumper goes to compress under normal recoil, then it's going to be behind the back of the ejection window at recoil, with the spent case bounced off the back of the ejection port window, and back into the action.

Washers are a good temp band-aid to trouble shoot, then the ideal solution is to pull the receiver extension, and shorten the end of the tube a few winds so it re-indexes everything correctly again (butt stock index/buffer retaining pin retention), while at the same time, stops the face of the bolt short of the back edge of the ejection window.


And why is the problem now happening,

As stated, could have been a new spring that temp band-aided the problem, or just the buffer bumper is now softer/slightly compressed shorter, and now allowing such.

Bottom line, if you take a look at the spent case that is stove piped, you going to see a nice smile face dent in the case just short of the rim section. That is where is tagged the ejection port window on the way out, and cause it to be deflected back into the action. Stop the spent casing from tagging the back of the ejection port window (bolt stopping in front of the port window) and you will have solved the problem.

To add: Obo2 had you dialed in way back on the solution, and why you did not listen to him is beyond all of us.


I didn't disregard him! There has to be a reason why now after thousands of rounds and multiply cleanings from tube to barrel, that this has started to happen. I don't believe that the moons happen to align right to make this happen. I did add a quarter to the tube and it is now working fine. So now I must figure out now what is out of spec. I did compare the buffer to a new one and they look identical down to the height. If I am to shave the extension tube how the hell do you do it to keep the rim to hold down the pin still and still get enough to change anything.

007Kevin
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Posted: 7/3/2012 9:18:12 PM
Post back to let us know how the spring worked out.


Where is this "bolt face should be a 1/4-3/8inch in front of the ejection port when pulling the charging handle back" thing come from??? Both carbine rifles I have, one mil-spec tube and one commercial, the bolt goes behind the ejection port and I do not have stove-pipe problems. The only one that is 1/4" in front of the ejection port is my built lower with Magpul PRS stock and a LaRue Stealth upper.

If the extension is the same as another then I don't see why shaving it down is going to help other than a time waster band-aid. If you have a collapseable stock you don't have much room to lose and still get the fully collapsed position.
Jdurzua
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Posted: 7/3/2012 9:31:00 PM
Originally Posted By 007Kevin:
Post back to let us know how the spring worked out.


Where is this "bolt face should be a 1/4-3/8inch in front of the ejection port when pulling the charging handle back" thing come from??? Both carbine rifles I have, one mil-spec tube and one commercial, the bolt goes behind the ejection port and I do not have stove-pipe problems. The only one that is 1/4" in front of the ejection port is my built lower with Magpul PRS stock and a LaRue Stealth upper.

If the extension is the same as another then I don't see why shaving it down is going to help other than a time waster band-aid. If you have a collapseable stock you don't have much room to lose and still get the fully collapsed position.


Stopping the bolt from going all the way back did fix the ejection issue. I went to the range and shot about 20 rds and had the first malfunction. I installed a single quarter in the end of the buffer tube. I then fired 100 rds without a hick up. Every casing placed on the same spot after that. the rifle shot like new. I also noticed that the bolt carrier was hitting the lower receiver. All this was done with the new buffer spring installed.
Dano523
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Posted: 7/3/2012 10:02:41 PM
[Last Edit: 7/3/2012 10:31:08 PM by Dano523]
Originally Posted By Jdurzua:


I didn't disregard him! There has to be a reason why now after thousands of rounds and multiply cleanings from tube to barrel, that this has started to happen. I don't believe that the moons happen to align right to make this happen. I did add a quarter to the tube and it is now working fine. So now I must figure out now what is out of spec. I did compare the buffer to a new one and they look identical down to the height. If I am to shave the extension tube how the hell do you do it to keep the rim to hold down the pin still and still get enough to change anything.



Receiver extension thread size is 1 3/16"- 16 pitch., So, 16 threads to the inch, which each thread being .0625" wide.

So it comes down to working in .0625 increments to shorten/face the tube on a mill to maintain the same index of both the butt stock index and the front of the tube to the retaining pin for retention at it is now.

You stated the the bolt face is now flush with the back of the ejection port, and we want to have it 1/4" forward of the back of the ejection port by shorting the tube, so 1/4" coverts to .250", and since that number is dividable by .0625 cleanly (4 X .0625=250), it comes down to shorting the tube 4 winds or .250". If the face of the bolt is slightly behind the face of the bolt, the we can take off another wind./0625 off, with the new trim length being .3125" instead.

And again, we are looking for the face of the bolt to stop between 1/4" (.250") and 3/8" (.375"). and just need to work in the .0625 lengths to maintain the same index of the tube now to the butt stock and buffer retainer index at is currently is.


To add, if you want to move the end of the tube closer to the center pin of the buffer retainer, subtract that amount from the trim number.

So here, lets say that the the end of the tube is .065" from kissing the center pin of the retainer, and we are going to face the end of the tube .250" back, the new set back length would be .1875".


So that answers the how much, and the how to shorten part, either mill to set back the tube the needed amount, or just wrap a layer of masking tape around the front of the tube, use a set of calipers to measure back to scribe in a line, then break out the hand tools to set the face back the needed amount (back to the marked line).

Posted By PlaymoreMinds:

'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...

<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
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