AR Problem...

M

marc4311

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Ok so i have posted before about this but havent fixed the problem (mostly because i havent been to the range in a year, due to work. I have an AR-15 LMT CQB-MRP and have experienced the following problem... I NEED HELP WITH THIS

The first magazine of ammunition fed well, I was shooting slowly and taking time in-between shots. However, the next mag of 10 jammed about 3 rounds into it (shooting these rounds a bit quicker than the last). The spent brass didn’t eject and the bolt started to carry a new round up the feed ramp. So I pulled the charging handle back and it didn’t eject, so I had to lock the bolt back, drop the mag, and shake those suckers loose. Then I inserted the mag, released the bolt and fired a round, and it happened all over again. So I try once more without success. My remedy was to switch mags. That didn’t help, it still jammed with either magazine.

I have a pic of it but how do i post it?
 
Hmmm this thing has barely been fired though..i would say, maybe, 30 rounds successfully..i shy away from shooting it when the problems started.
 
I don't think a pic is necessary.

Need more information:
What ammunition? New or Reloads?
What mags are you using?
Does it happen with all mags?
You only have 2 mags?
Did this problem just start... was the rifle fine before? How many rounds have you put through it before with no problems?

From what you've said, it sounds like the extractor is slipping over the case rim.
What's the barrel length on your AR?
Did you buy the rifle new or used?

:)

More information is a good thing.
 
Hey G37 - The barrel is 10.5 and the rifle was bought new.

Ammunition was New. American Eagle, 223 - 55 grain

Mags - not sure what they are but i have 3, 10 round mags and 5 of the 30 lanced to 5, and of course the 5 round mags it came with. Yes this happens with all mags.

The problem started on the first mag on the first day at the range.

Im a newb with rifles so it might not be a big problem but i def have no idea...maybe a lube problem is what i was thinking
 
Ok...

Well, we can rule out magazines, and ammo.
Your rifle is also relatively new. (By the way, where did you buy it from? Questar?)

Is it safe to say that this is the problem you are having:

"Frequently (a few times every 10 shots), the spent brass is left inside the chamber and a fresh round is being jammed up behind it?"
 
Failures to eject and double feeds mean you need a stronger extraction spring setup.

Extraction springs are meant for full-length 20" rifles and not the more sudden extraction of a 10.5".
 
Does your rifle have a different upper and lower where you have an offset screw so they fit together properly?

Also, Do you keep rounds in your mags keeping a constant pressure on your springs?
 
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sigger69 said:
Failures to eject and double feeds mean you need a stronger extraction spring setup.

Extraction springs are meant for full-length 20" rifles and not the more sudden extraction of a 10.5".
Click to expand...

X 2 .i got this problom with my 7.5" AR.
new bolt and new barrel.
but all single round FTE.like you said.
so i find one same size plumber O ring put it around the extractor spring.( like the D-fender .but quster is sold out,)
than fix the problom.
No more FTE now.
Try it .cause if not working. you can take it out.
Or you can try this https://shopquestar.com/shopping65/shopexd.asp?id=829&bc=no
 
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G37 - Yes it is safe to say that is the problem -

Sigger69 - sooooooooo what do i do about the extraction spring setup? Buy something im guessing?

CSDIV - not sure about the upper and lower (i dont remember) but theyare both LMT. If your asking whether or not i keep rounds in my mags at all times, the answer is no...I load em up at the range.
 
Well... you're going to have to learn how to field strip that rifle. Get intimate with it.

The cheapest and easiest thing to try as mentioned above, is to buy a small rubber O-Ring from Lordco and sandwhich it between the bolt and extractor (the extractor spring sits in the middle of the O-Ring); there should also be another piece of rubber inside that spring... looks like a mini foam ear plug.

O-Ring_&_Extractor_thumb.jpg


Hopefully this helps.

Basically the Bolt is being hammered back fast and hard (due to the short barrel) and your brass is still strecthed and locked inside the chamber... the extractor is slipping over the rim of the brass, unable to extract it. The O-Ring puts more force on the extractor and will hopefully solve your problem.

Short-barreled AR's definitely require some preventative maintenance, similar to an Airplane :) You replace parts after certain periods of time/usage to ensure reliability.

The 20" AR's can go forever ;)
 
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Hey guys, thanks a lot of your help, Very much appreciated. I must admit that I need to learn more about the insides of the rifle and this forum def helps me out with it.

I will order the D-Fender ring and work my way through installing it....you will hear from me again if i cant lol.

Just to be sure...all im looking for is a "D-Fender" ring? No other fancy name for it or like model?
 
weak extractor...

You can put up a WTB ad here on CGN parts and see what you'll find.
Check out on youtube how even a 9 years old girl can field strip
the AR in 20 seconds. Best place to learn from.
Regards,
Robert
 
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