AR15 jamming / Malfunctioning

[C4MC]

I recently purchased a new AR from a reputable company. The first time I took it out to shoot I had several cartridges jam. The cartridge would be jammed at about a 45% angle. I was using new PMC .223 ammo.

Is this normal? Do AR's require some break in to get them working properly? I fired about 45 rounds and it jammed 3 or 4 times. Should I be concerned? Any recommendations?

 

[z71rat]

Re: AR15 jamming.

It doesn't sound like an AR problem. Sounds possibly like a magazine problem. What mags are you running??

DK

 

[z71rat]

Re: AR15 jamming.

Another issue that it "might" be, would be the feed ramps. Look at the magazines first. Take out the spring assembly, and stretch the spring to make it hold the rounds tighter. The force of the BCG will still easily strip the rounds.

If it is your feed ramps, a slight buffing with a coned dremel buffer and some buffing compound will do wonders. If your AR has the M4 feed ramps, then I doubt that would be the problem.

Check them both out, but I believe from what you are saying, that it is more than likely a mag problem.

DK

 

[pwc001]

Re: AR15 jamming.

I just got a 20 round Pmag that is causing the same problem, the gun runs fine with other 30 round Pmags and regular mags. I would start by trying different magazines and see if that helps. Good luck.

 

[Solid_Squirrel]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pwc001</div><div class="ubbcode-body">I just got a 20 round Pmag that is causing the same problem, the gun runs fine with other 30 round Pmags and regular mags. I would start by trying different magazines and see if that helps. Good luck. </div></div>

I believe the 30rd has constant curvature internals, while the 20rd does not.

 

[z71rat]

Re: AR15 jamming.

Have you looked at any of the jammed cases?? If there is signs of the bolt catching the case body and not the head, then you could just have a weak buffer spring.

Check some stuff out in detail and get back with us on what you find out. I am sure we can kill some brain cells and fix it!!

DK

 

[z71rat]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pwc001</div><div class="ubbcode-body">I just got a 20 round Pmag that is causing the same problem</div></div>

Again, spring tension means everything!! PMags are not above needing a good stretching...

DK

 

[Redcreek1]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rootney</div><div class="ubbcode-body">I recently purchased a new AR from a reputable company. The first time I took it out to shoot I had several cartridges jam. The cartridge would be jammed at about a 45% angle. I was using new PMC .223 ammo.

Is this normal? Do AR's require some break in to get them working properly? I fired about 45 rounds and it jammed 3 or 4 times. Should I be concerned? Any recommendations? </div></div>

What brand of AR? Barrel lenght? Carbine, Mid-Length or Rifle length gas tube? Fixed A2 or colapsible stock? Did you properly lube it before firing?

A bit more info would go a long way in providing advice on what to check.

 

[pwc001]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: z71rat</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pwc001</div><div class="ubbcode-body">I just got a 20 round Pmag that is causing the same problem</div></div>

Again, spring tension means everything!! PMags are not above needing a good stretching...

DK </div></div>

I am not worried about mine, only mentioned it as an example, that even new mags can have problems, even Pmags.

 

[USACS]

Re: AR15 jamming.

Jam goes on toast. Your rifle is malfunctioning.

Is the malfunction happening during loading or extracting/ejecting?
Do you have extended feed ramps on the upper receiver and barrel?

Before you start to replace parts, figure out where the problem is. Don't put the cart before the horse. You need to determine what the problem is and how it's happening before you can start to fix it.
The above listed questions like make, model, magazine, etc are all important information. Without more detailed info, diagnosing the problem is difficult to impossible if we can't see it happening or have it accurately described.

In re the break-in question: the short answer is NO. ARs should function properly from the get-go. They just "wear in" as you use them.

 

[cz777]

Re: AR15 jamming.

sorry to hear this .ok the spent cartridge is hanging out the extracting port ...pull out the bolt carrier see if gas key is NOT loose or leaking next look at gas rings -do the gas ring test ...next is the gas block/tube is clear/clean ???blow some air down the tube from carrier side feel air out of the front barrel?? lub the weapon well use of good oil like Mobil 1 which does not carbonize ...

 

[creids98292]

Re: AR15 jamming.

If the gas block is adjustable, turn the set screw counter clockwise 1/4 turn till your brass ejects out to the 3 o'clock position. if not a lighter recoil spring or heavier loads may help. JP enterprise's gas blocks rock for solving these issues.
Also if its carbine length system try a pigtail gas tube. I've seen this with ammo and mags also. Best to rule out all the above that doesn't cost money.

 

[USACS]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cz777</div><div class="ubbcode-body">lube the weapon well use of good oil like Mobil 1 which does not carbonize ... </div></div>
It would be good to note that one should use full synthetic oil, as opposed to standard petroleum or synthetic-blend.

 

[seta8967]

Re: AR15 jamming.

I did have a emag that was slightly molded wrong (not even magpul is above equipment failure or malfunction) and was slightly deformed and the bolt would hit the magazine causing feeding issues. I contacted magpul and sent them a picture, they sent a replacement, didn't even want the old one back.

 

[C4MC]

Re: AR15 jamming.

This is my first AR so I don't have a clue about them. The gun is an RRA Predator Pursuit 20" barrel with rifle length gas tube. It is bone stock. It seems to extract cases fine, the problem is feeding.

The 20 round mag that I got with it is stamped NHMTG, Hartford CT. and has a manufacturer date of 3/09. I am wondering if the mag could have been switched somewhere along the line like at the dealer since I just purchased the gun about a month and a half ago. Hard to believe that RRA would have a mag sitting around from March 2009. When I picked up the gun I called RRA since the mag appeared to have more wear than one would expect from just test firing. They say mag probably got switched. Dealer says no way it could have.

Gun has a fixed A2 buttstock. I did not lube it before firing. It seemed to have oil on the mechanical parts so I did nothing in terms of lubrication. Pushed a patch down barrel to remove any crud and started shooting it. I guess I should just clean and lube it and get a different mag and see if it functions properly.

 

[Beef_Supreme]

Re: AR15 jamming.

Check those gas rings regardless. I have seen off the shelf guns not run properly just because the ring gap was aligned. Bolts are assembled by monkeys at a bench who rarely pay attention to details like bolt ring end gap. Try this- load one round in mag, chamber from open bolt and shoot it. If it locks back on empty mag then your system is pressurized and problem lies elsewhere.

 

[Inogame]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rootney</div><div class="ubbcode-body">This is my first AR so I don't have a clue about them. The gun is an RRA Predator Pursuit 20" barrel with rifle length gas tube. It is bone stock. It seems to extract cases fine, the problem is feeding.

The 20 round mag that I got with it is stamped NHMTG, Hartford CT. and has a manufacturer date of 3/09. I am wondering if the mag could have been switched somewhere along the line like at the dealer since I just purchased the gun about a month and a half ago. Hard to believe that RRA would have a mag sitting around from March 2009. When I picked up the gun I called RRA since the mag appeared to have more wear than one would expect from just test firing. They say mag probably got switched. Dealer says no way it could have.

Gun has a fixed A2 buttstock. I did not lube it before firing. It seemed to have oil on the mechanical parts so I did nothing in terms of lubrication. Pushed a patch down barrel to remove any crud and started shooting it. I guess I should just clean and lube it and get a different mag and see how if functions properly. </div></div>

Check the BCG, give her a good clean and lube and try to get a hold of a different mag - even if you just borrow one from a buddy to try out. That's where I'd start.

 

[Alpine 338]

Re: AR15 jamming.

Look at the feed lips on your magazine, if it's aluminium they can easily get bent (usually in) from a drop or bump, and that can cause you problems with feeding. The other thing is AR's don't usually like soft tip ammo, so I'm not sure what you're using other then you said PMC 55-gr. Stick with FMJ, JHP, or any of the polymer tip bullets. Good advice already given on lubrication, and make sure you use light oil lube, or dry film lube. Stay away from heavy oil and grease. Some people have had good luck with the TW-25B synthetic grease, but I've only used it on pistols.
I have used TriFlow for years on my AR's, but have recently started using Slip2000 EWL.
Some rifles with gas piston systems require break-in, but never heard of a DI system needing a break-in.

 

[LS6TT]

Re: AR15 jamming.

I had this same issue on two of my builds. (check my history there is a topic about it) long story short mine was a gas block issue on both builds. be it out of alignment or whatever the issue was. I removed the gas blocks reinstalled, oiled the BCG and all was well after that.

I tried with every mag i owned, buddies mags, etc.

 

[USACS]

Re: AR15 jamming.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Beef_Supreme</div><div class="ubbcode-body">Check those gas rings regardless. I have seen off the shelf guns not run properly just because the ring gap was aligned. Bolts are assembled by monkeys at a bench who rarely pay attention to details like bolt ring end gap. Try this- load one round in mag, chamber from open bolt and shoot it. If it locks back on empty mag then your system is pressurized and problem lies elsewhere.</div></div>
Experts abound have debunked the gas ring gap alignment "malfunction". I have personally tried it on several rifles and have never been able to induce a malfunction. Further, upon pulling the bolt out, the rings were moved and the gaps no longer aligned. The rotation and movement of the bolt moves the gas rings.
If this were such a catastrophic issue, why do all reputable companies continue to use standard mil-spec gas rings?

If an off-the-shelf rifle has any malfunction related to the gas rings, it's not going to be because of the gap unless the rings themselves were out of spec. There were likely other issues at play.
Inspecting gas rings is important, but the gap alignment issue has been debunked.

 

[BittenbytheBug]

Re: AR15 jamming.

Do you know anyone else with an AR15 platform? You could try running your mag in their rifle and see if they come up with the same issues.

I'm wondering if you aren't under gassed? Does your bolt go all the way to the rear when it attempts to extract the round?

 

[11B101ABN]

Re: AR15 jamming.

Knowing the brand of rifle might be helpful.

 

[DuceNova]

Re: AR15 jamming.

I built an AR15 with an ATI lower with Model 1 Sales parts throughout it( complete upper, trigger kit, 20" barrel, six way adjustable stock, and small parts kit). It also has a Nokick Enidine recoil reducer because I have retinal detachment issues with both of my eyes.

Before I built it I bought a S&W M&P AR15.

The M&P has had no problems with all of the mags that I own. However, the ATI had problems with latching the plastic 30 round mags but not the 20 round or the one 10 round that came with the M&P. Once I could get the mags to latch, every once in a while it would have a feed malfunction similar to what you are talking about.

I called ATI and they said to send them the rifle and they'd take a look at it. When I got it back they had slightly machined the mag well so that the mags set higher up in the well so now the plastic mags work fine.

I also found that the ATI seems to want to be lubricated more often until I put a chrome bolt carrier assembly from Sarco in it (I was switching the bolt carrier assembly out of the M&P into the ATI until I could afford another bolt carrier assesmbly).

I was also having problems with failure to lock up every so often with some of my reloaded rounds. I inspected ALL of my rounds (I check every 20 rounds while reloading) and found a few were slightly over length so I ran them all through the reloader's last two dies and the feed problem went away as did the "failure to lock up" problem went away.

IF your problem persists, I would call the company that made it and ask them what could be wrong. I'll bet they tell you to send it to them to fix it as any good company would want to fix one of their products.

 

[Beef_Supreme]

Re: AR15 jamming.

Gas Ring alignment being debunked by who? I had one Saturday that someone brought me and the rings were aligned. It ran 'sometimes,' I checked the rings and they were all aligned, offset everything and it ran like a champ.
DPMS had an M4 that ran with only one ring total, but that was one upper and no others did it. Tolerance stack comes into play. Why not just start with the cheapest easiest potential problem and eliminate it in sequence?

 

[SHO~BIZ308]

Re: AR15 jamming.

feed ramps

 

[Who Dat]

Re: AR15 jamming.

Start fresh, take the weapon apart and clean it, use a lubricant that is a CLP. I use TriFlow it has a ton of teflon in it and can take the high heat. I agree with the other guys an AR will shoot on how you treat it right out of the box sort of like setting the memory for the weapon. Clean it thoroughly, do not over lubricate the parts. Lubricate the bolt carrirer on the four flat spots with a drop of lubricant on each flat spot (This is where it rides on the receiver). A drop of lubricant on the bolt where it contacts the bolt carrier where it rotates. Do not put any lubricant on the gas rings, any place you put lubricant it will draw carbon to it. Place a small amount of lubricant on the ears on your charging handle where it rides in the slots in the receiver. I usally put a drop on my finger and wipe it on both. That much lubricant will handle 500 rounds through the weapon like it is nothing. If it does not function do like the rest of the guys are instructing start with your mags first, not every mag is functional right out of the wrapper. I use the PMAGS for duty and they have all been function tested because my butt depends on them. For training and quals I use the aluminum bang me up and drop on the concrete mags. If the mag does not work scrap it and use another. If the weapon still does not function next two things are the gas system and extractor. A mis-aligned, bent gas tube or mis-aligned gas block will cause a lot of problems. Smith and Wesson had some weapons that got by their quality control and they recalled them because of this. Caused problems for gents on my job who carry S&W. Gas systems are a finicky thing, they may work fine up until the tolerences change from carbon build up then it will show its backside. Check the extractor before jumping into the gas system it is easy to get too and the parts are cheap. One thing to remember oil on the weapon from the factory is normally used to protect the weapon during storage and may not be the proper lubricant for operating the weapon.

 

[rpk762]

Re: AR15 jamming.

I would try a few different mags. My friend has a AR that would jam like you are stating with many different mags. Back then we did not have P-mags. What his problem was his mag catch was screwed in too far. I backed if off so it still caught the mag but did not drag on the ammo. That solved his problem might be something to look at.

 

[doc76251]

Re: AR15 jamming.

Bone Stock = Bone Dry.

Dump the BCG in a can of motor oil pull it out, wipe it off and fire it.

If that doesn't work see all the above.

New AR's w/o lots-o lube don't run.

Cheers,

Doc

 

[Lawrence]

Re: AR15 jamming / Malfunctioning

I see this all the time. First thing I do is switch to a good mag. Second thing I do is to look at rec.& bbl. feed ramp compatability. Third thing I do is install a extractor upgrade, which usually solves the problem. This is common in production carbines, but am seeing it more in the rifle length production stuff. I have noticed over the last 3 years of a influx of non-USA parts being used by a few Reputable Mfgs. Don't blast me on this, I work on these things all the time & see poor metal wear on parts often which is compared to throat erosion, aka - rounds down the tube., over time you can tell what a crap part is...hope this helps. Gas tube / system problems are caused by poor work.

 

[varmint53]

Re: AR15 jamming / Malfunctioning

This is the first thing you need to try, load one round in your
clip and fire it and see if the bolt locks back. That will tell if it is getting enough gas,and that your buffer spring is not to strong.then come back and tell what is happening

 

[cwillits505]

Re: AR15 jamming / Malfunctioning

+1 to Tim above ^^^^^ I literally do nothing but ARs on a daily basis and have seen this a million times with a million different reasons but one thing is for sure, you have a gas problem.. hence- BCG comes back far enough to eject round partially, then backforward just in time to catch it on the way out, and as said by many above, doesnt have enough gas to be pushed all the way the rear and never gets the full force forward that it is meant to have.. can be caused by a ton of things, but usually from a factory gun it shouldnt be a gas line issue, but more than likely a mag issue.. also check your mag catch.. put a mag in and see if you can pull it out by hand.. ive had a gun in the past do this exact thing all because the mag catch was bad and the gas pressure was escaping through the magwell!