AR help / suggestions

[jrebel]

I built an AR last year and have absolutely loved it until this last month.  All of a sudden it is having a problem seating and extracting cases.  I have disassembled and cleaned everything, re-oiled and put back together.  Well it did not solve the problem.  It appears the bolt and extractor are not grabbing rounds as they are being picked up out of the mag.  The cases are showing pretty large gouges on the rim of the case and the bullets are being gouged / scared upon being seated in the action. 

I have probably put 300-400 rounds down the pipe and have maintained it like all the rest of my guns cleaning religiously. 

Suggestions??

Thanks

jrebel

[cwuwildcat]

Same ammo the entire time?  Have you checked your buffer?  Same issue with different mags?

[cwuwildcat]

Here might be some help;

http://thearmsguide.com/6827/ar-15-upgrading-extractor-spring/?utm_source=rss&utm_medium=rss&utm_campaign=ar-15-upgrading-extractor-spring&utm_reader=feedly#prettyPhoto

Here's a link to the embedded video.  AR-15 - Troubleshooting My Pistol/SBR - Part 2  Is this similar to your issue?  It starts failing about 2 minutes in.

[Biggerhammer]

Same ammo the entire time?  Have you checked your buffer?  Same issue with different mags?

First several questions I would have asked?

Is this with factory ammo or handloads? If it's with handloads have you changed your FL die adjustment or dies?

[jrebel]

All Factory ammo....55 grain hornady v-max.  Prior to this ammo it was mixed bag 55 grain fmj ammo.  All brass case, it has never had steel case ammo cycled through it. 

I fired approx 100 rounds at the range with the hornady and it cycled fine.  I had my first problems when out coyote hunting in really cold weather.  I would go to rack a round in and it would push the round  into the chamber but would not seat in the bolt.  I tried using the forward assist button and it still would not seat.  I had to release the mag and rack the action again (some times a few times) before it would grap the round.  At this point it would fire and eject the case but would repeat the above action.  I have tried different mags (magpul and steel) and it doesn't seem to matter. 

I have not tried my other ammo...which maybe I should. 

I have checked the buffer and buffer spring and cannot find anything wrong with it.  I have thought maybe a stiffer spring would solve the problem but don't know why all of a sudden what was working just stopped. 

I was leaning toward the extractor / bold be faulty?  but again, it worked flawlessly until this started happening. 

 

[Bmcox86]

Have you checked the headspace?

[Biggerhammer]

You mentioned cold weather. Are you shooting it fairly wet? Is the cold weather reacting with your lube and causing a"Sticky" effect. Slowing the bolt carrier group. I've seen that happen. Can you take a small crew driver tip and move your extractor on your bolt in and out or is it jammed?

[FC]

Same ammo the entire time?  Have you checked your buffer?  Same issue with different mags?

First several questions I would have asked?

Is this with factory ammo or handloads? If it's with handloads have you changed your FL die adjustment or dies?

I would have asked the same two questions. I had some Aguila that wouldn't chamber in my AR and one round of Brown Bear.

[cwuwildcat]

Do you have another BCG that you can swap in, and see if you have the same issues?  Regarding the buffer, I think the issue would be with the weight of the buffer, not the spring strength.

[jrebel]

Do you have another BCG that you can swap in, and see if you have the same issues?  Regarding the buffer, I think the issue would be with the weight of the buffer, not the spring strength.

I don't, I was going to swap bold carrier groups with a buddy and see what happens as a trouble shooting method, but have not gotten to it yet.  I could do the same with the buffer.

Have you checked the headspace?

I haven't....I bought the upper as a complete upper.  I am not sure I even know how to check the head space as this is my first AR ever.

You mentioned cold weather. Are you shooting it fairly wet? Is the cold weather reacting with your lube and causing a"Sticky" effect. Slowing the bolt carrier group. I've seen that happen. Can you take a small crew driver tip and move your extractor on your bolt in and out or is it jammed?

I am not running it very wet at all as all the literature I have looked at said not to.  The extractor moves fairly easily.  I took the bolt completely apart and cleaned the extractor and did a function test on a piece of brass.  It seams to be working well when not in the gun. 

I will take a picture of the brass and bullet marks...maybe that will help.

[cwuwildcat]

Here's a little something on the buffer/spring issue.  Probably not the issue, since things were working for awhile and then went downhill, but you never know and it only takes a minute or two to check.  Find out what your buffer weights.

http://www.gundigest.com/guns/rifle-reviews-articles/gunsmithing-the-ar-3-tips-for-buffers-recoil-springs

[jrebel]

Not great pics but you can see the markings.  The brass is being shaved / worn from the back.  The bullet is showing spiral marks on the brass.  This could have been happening from the first shot and I have just now noticed due to the loading problem. 

With all this being said the gun shoots lights out....best group was three shots that could be covered by a dime at 100 yards off a bench. 

[Biggerhammer]

When a bullet looked like that. It's either the mag isn't seating correctly or for some reason the bullet is riding the front of a metal mag when it's feeding either that or it's a feed ramp issue as in m4 cuts on the receiver but not on the barrel?? Hmmmmmmmm. Look into the feed ramp area and see if it is a smooth transition from the M4 cuts in the receiver to the cuts in the barrel.

[snowpack]

Is there much play/wiggle in the magazine?  Are you shooting like you always have or resting on the mag, pushing it at an angle?

[Heredoggydoggy]

Sounds like a dirty chamber, or ammo that is bulged or out of spec, or lube that is getting sticky in cold weather.  Your primers look good--no sign of excessive pressure.  The gouge in the rim of the case looks like it is being done by the extractor when the bolt turns and "locks up".  Again, I would make sure the chamber is clean and the lube is made to function in cold temperatures.  ARs thrive on oil, but there should be none in the chamber.  I've had chambering problems with the wildcat cases I've made due to bulges in the reloaded cases, but never the .223.    Even my .223 reloads functioned perfectly, but I've noticed a lot of "growth" in case length in 223 fired cases....