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....

[mountainman]

What he said!

[Fl0und3rz]

I'd suspect a sticky or obstructed extractor causing the round to start to chamber at too high an angle to the chamber. As the round is coming off the magazine something appears to be preventing the back end of the case from coming up to the centerline of the bolt as it chambers. I had a similar issue with a marlin 1895, and the rounds had similar scratching.  A sticky extractor would explain the marks on case rim as the extractor is being forced over the rim. 

[mrolen]

I would start by full strip and clean of the bolt. some lube is to heavy in cold weather I have experienced this with frog lube. Try a different mag and possibly a new BCG, that is where i start with an ar with problems.

[Heredoggydoggy]

I would start by full strip and clean of the bolt. some lube is to heavy in cold weather I have experienced this with frog lube. Try a different mag and possibly a new BCG, that is where i start with an ar with problems.

   I'd suspect a lube problem.  We've had some very cold temperatures lately, and some lubes don't handle cold very well! 

[snowpack]

The difficulty for closing the bolt all the way, even using assist does sound like lube issues.  It makes it difficult to rotate and lock the bolt (and unlock it too).  That last 1/4 inch on closing is horrible if sticky.  The scratches on the ammo, factory ammo, looked like a bad feed angle, so I was thinking magazine alignment.

[jrebel]

Thanks for all the information.  I have a few upgrades on order now and I will be doing another thorough cleaning and better lubing with a new lube.  I can't imagine it has anything to do with the magazines as the mags have worked flawlessly prior to these episodes.  If the upgrades / cleaning / lube does not work I will try a different bolt / bolt carrier. 

For the diagnostic purposes I will try one thing and shoot, then try another and so on....I will update with the progress.  I hope I can figure this out.  I will say this...as much as I have enjoyed building and shooting my AR, I have never has a problem with my AK.  This AR thing can be frustrating.   

[6.8mmARHunter]

I know precisely what your problem is...

You have to swear off the 49ers. Everything will be good after that.

Totally kidding...

I've got nothing else.

[jrebel]

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.

OK...Well after a lot of tinkering and a few upgrades, I think I know what the problem is.  My bullets and cases are being scared by the lugs on my m4 feed ramps.  Next step will be to polish (find someone that knows how to polish) feed ramps and clean up the ramps where they meet the lugs.  My set up is a rifle upper with m4 ramp barrel extension.  My magpul magazines seat the bullets high enough that the bullet is not coming into contact with the receiver at all.  The copper and brass scaring is coming from the harsh angles at the ramp / lug area of the barrel extension. 

If I am right....this should fix all my problems.  I will post after I have had the ramps polished.

jrebel

[Biggerhammer]

When you posted the gouged up cartridge pics, I knew it has to be a feeding issue with the receiver cuts or the barrel extension cuts.

[jrebel]

Update....Problem solved!!!! 

Last week I spent a couple hours watching youtube videos and learning how to polish ramps and work on AR's.  Today I took the dremel and got to work (figured the worst I was going to do is mess up a barrel extension and maybe an upper) .  Spent a couple hours polishing the feed ramps.  Now they look really shine and are awfully pretty.  I readdressed the bolt and bolt carrier; recleaning and oiling the living piss out of it.  Everything was smooth as butter.  Next step was to feed ammo and see what happens.  I place a loaded mag in the well (pointing my muzzle toward the floor) and feed a round................JAM  !!  Try again.........JAM !!  Now I am pissed.  Inspect the brass and notice the makings on the bullet and brass are significantly better / lighter.  The brass on the head stamp is still marked up pretty well.  So needless to say I am now really pissed off. 

I decide to just buy a new bolt carrier group.  Drive to one of my new favorite stores (Stans Merry Mart) and purchase a nickle boron bolt carrier group.  Come home and replace the original bolt carier group.  Guess what......Cycled a complete mag with no issues.  Bullets still have very minor markings but all in all everything looks good.  Head stamp has no marks.  Problem solved....for some reason my bolt / extractor has gone bad.  Now to replace the extractor on the old bolt and see what happens.  If that does not solve the problem I will buy a new bolt.   If that does not fix the problem I will sell the complete pile of mess to the highest bidder!!  

jrebel

[Fl0und3rz]

Good to hear.  Please update with the extractor/bolt troubleshooting results, too.

[jay.sharkbait]

Update....Problem solved!!!! 

Last week I spent a couple hours watching youtube videos and learning how to polish ramps and work on AR's.  Today I took the dremel and got to work (figured the worst I was going to do is mess up a barrel extension and maybe an upper) .  Spent a couple hours polishing the feed ramps.  Now they look really shine and are awfully pretty.  I readdressed the bolt and bolt carrier; recleaning and oiling the living piss out of it.  Everything was smooth as butter.  Next step was to feed ammo and see what happens.  I place a loaded mag in the well (pointing my muzzle toward the floor) and feed a round................JAM  !!  Try again.........JAM !!  Now I am pissed.  Inspect the brass and notice the makings on the bullet and brass are significantly better / lighter.  The brass on the head stamp is still marked up pretty well.  So needless to say I am now really pissed off. 

I decide to just buy a new bolt carrier group.  Drive to one of my new favorite stores (Stans Merry Mart) and purchase a nickle boron bolt carrier group.  Come home and replace the original bolt carier group.  Guess what......Cycled a complete mag with no issues.  Bullets still have very minor markings but all in all everything looks good.  Head stamp has no marks.  Problem solved....for some reason my bolt / extractor has gone bad.  Now to replace the extractor on the old bolt and see what happens.  If that does not solve the problem I will buy a new bolt.   If that does not fix the problem I will sell the complete pile of mess to the highest bidder!!  

jrebel

When you cycled the rounds this last time were they rounds that had been previously "tested" in the rifle?

[jrebel]

Update....Problem solved!!!! 

Last week I spent a couple hours watching youtube videos and learning how to polish ramps and work on AR's.  Today I took the dremel and got to work (figured the worst I was going to do is mess up a barrel extension and maybe an upper) .  Spent a couple hours polishing the feed ramps.  Now they look really shine and are awfully pretty.  I readdressed the bolt and bolt carrier; recleaning and oiling the living piss out of it.  Everything was smooth as butter.  Next step was to feed ammo and see what happens.  I place a loaded mag in the well (pointing my muzzle toward the floor) and feed a round................JAM  !!  Try again.........JAM !!  Now I am pissed.  Inspect the brass and notice the makings on the bullet and brass are significantly better / lighter.  The brass on the head stamp is still marked up pretty well.  So needless to say I am now really pissed off. 

I decide to just buy a new bolt carrier group.  Drive to one of my new favorite stores (Stans Merry Mart) and purchase a nickle boron bolt carrier group.  Come home and replace the original bolt carier group.  Guess what......Cycled a complete mag with no issues.  Bullets still have very minor markings but all in all everything looks good.  Head stamp has no marks.  Problem solved....for some reason my bolt / extractor has gone bad.  Now to replace the extractor on the old bolt and see what happens.  If that does not solve the problem I will buy a new bolt.   If that does not fix the problem I will sell the complete pile of mess to the highest bidder!!  

jrebel

When you cycled the rounds this last time were they rounds that had been previously "tested" in the rifle?

Same manufacturer and same ammo, but batch..... (if that makes sense).   The other stuff that was jamming up has some horrible damage to the brass on the head stamp.  I am not to sure it will feed in anything at this point...it may need to be trashed. 

Anyone else ever have a bolt / extractor just go bad???  Worked great for the first 3-400 rounds.