Help me with an AR malfunction

[chris in va]

1000 rounds through my M&P so far, three 'jams' for lack of a better term.

Basically I'll be slow firing through a mag and the trigger won't pull. With a bit of force I can pull on the charging handle to pull out the malf round, which is bent slightly and has severe scrape marks on the case and bullet.

Is it something I'm doing with the reloads or just something to be cleared and carry on? Would a couple taps on the mag help?

Lee FLD, FCD, 2.23oal with 55gr FMJ and range pickup brass. Magpul mags.

 

[B-RAD]

Magpul mags - CHECK

Are you full length resizing to the max for you AR-15 (as in your die is only 1/16" of a turn above your shellholder?) Do you keep your bolt clean and lubed? (If your in "battle" just spray some "triflow" and soak your bolt - I guarantee you can get another 500 rounds through your gun with that thing dripping wet with triflow, again.. for "battle") Are your feed ramps on your barrel extension polished? (with a dremel and some rubbing compound) Is your buffer spring strong enough (try a tubbs flatwire spring). Are your loads hot enough or is your gas port large enough? (dremel will again help you here...) Do you have an adjustable gas block? (if so crank it up a few turns) Do you see any wear in your upper from your bolt carrier? (if so find the error and polish) Do you have grease on your buffer spring?(if not do so and grease up your buffer aswell) Where is your brass ejecting from your gun... straight to the right or back? or straight to the right and forward? You will want it to be to the right or back for proper operation. Is the rounds that do fire just fine dented at all?

Answer these an I'll give you an answer? Not sure how many people know the proper operation of an AR-15 here.....

Note: Sell the gun and stick with a custom built AR-15 to be really happy...

 

[cracked butt]

Is the shoulder of the round protruding?
.223 cases are pretty delicate, I've bent a few when getting lazy with operating the press.
The one malf I've had was from using a Lee turret press and allowing the handle to drop when running the case up into the powder charging die. What happened was the inertia f the ram was enough to peen back the shoulder when it stopped at the top of the stroke in the die. I caught myself doing this once, unfortunately one of the cases made it into my ammo box and it jammed up my rifle solid during a match- I had to hold the charging handle back while slamming the butt on the concrete to extract it. Can't remember if it got scraped up in the process.....

 

[chris in va]

Are you full length resizing to the max for you AR-15

Yes.

Do you keep your bolt clean and lubed?

Yes. It gets a thorough cleaning/lube before every range trip.

Brass ejects around the 2 o'clock position in a fairly neat area.

No grease on the buffer spring.

Brass is lightly dented at the case mouth, if at all.

Next time it happens I'll take a picture for you guys.

 

[Jim243]

I'll be slow firing through a mag and the trigger won't pull. With a bit of force I can pull on the charging handle to pull out the malf round, which is bent slightly and has severe scrape marks on the case and bullet.

Chris, It sounds like your rifle has not gone to full battery (trigger won't pull), check your feed ramps or the rounds are getting hung in the mags somehow. Or it could be just too light a load to cycle your rifle properly.

Jim

 

[HiBC]

I'd say be selective about who you follow.I'd be especially leary of folks who aren't sure anyone here knows how an AR works,but thinks you might need to take a dremel to your gasport.Or generally thinks you ought to take a dremel to anything you can't throw away and start over on.
How about this idea.Drop the bucks for about two boxes of good US made mil-spec ammo(assuming your rifle says 5.56 on the bbl) factory loads.Try one box of 20 with the mag you have.It will either work,or not.If it works,your handloads need work.We can talk more later.If it does not work,try a different mag.I like the magpuls just fine,but if a buddy has a mag that works good,try it.Or buy a different mag.
If your rifle fails to work with good factory ammo and a change of mags,good chance you have a rifle problem.Till then,I would suspect something about the range pickup ammo,and any 1 magazine can be bad.
Also,if you had been shooting some coated steel cases,you may have some gunk in your chamber.Actually,through inspection,and maybe a session with a chamber brush,I'd eliminate that first.You might check your ejector plunger works free in the bolt face.Sometimes hot loads cause little scrapes of brass to foul the ejector.That could inhibit lockup and deflect the case.
Later.

 

[HiBC]

Also,do not bump your seater die on the shellholder.They have a built in crimper,and you can cause problems.Ram up,brass in the shellholder,screw the die in till it contacts the neck,then back up some.
I like it that you chose the Lee fcd.Not too heavy on it!

 

[cryogenic419]

These jams that are happening...are the rounds chambering, just maybe not all the way? First thing that is popping into my mind is are your seating and crimping dies set up correctly? I know when I was first starting out with reloading I had the crimp set way too deep and it was actually crushing/ bulging the cases at the shoulder, some would chamber, some wouldn't. I had to compare a loaded round to a resized piece of brass to really spot it.

You say you're running Pmags...are you just using one mag or has this happened with different mags?

Have these issues occured with factory ammo?

Just a thought, try to walk through the problem and find a solution before taking a dremel to your gun. As suggested below it may be something as simple as a simple tweak to your loading process, the gun may need cleaned or lubed.

 

[riverwalker76]

First off ... I'm going to step in here, and try and clarify something.

If I read this correctly, you are full length sizing, but you ARE NOT using a Small Base die ... correct?

If so, you are doing everything ok. I would never use a small base die on a 5.56 or 223 Remington AR. It's simply not needed.

Next, I had this exact problem with a recent build.

Let me ask you this before I go on ....

Have you recently removed your depriming pin in your die for ANY reason, or have you every deprimed any 'hard to get out' primers?


Also, next time it does it .... eject the magazine and spray a little CLP in the chamber before attempting to eject the round. What is happening there is that the ejector is already grabbed ahold of the round, and you are fighting that tiny piece of metal!


It's not the magazine!

 

[Edward429451]

What is happening there is that the ejector is already grabbed ahold of the round, and you are fighting that tiny piece of metal!

I'm sorry, but this does not make sense. The ejector does not "grab" anything.

 

[44 AMP]

If the trigger won't pull, that means the bolt carrier is not full forward. The rifle is not "in battery" (locked shut) and the fact that it won't fire is a very, very good thing. Its working the way it is intended to!

Now, why doesn't the bolt shut all the way on some rounds, and not others? That's the question, isn't it?

You are full length resizing...so, ok there.

Have you checked your brass for length? And, are they all a uniform length, and below max?

Cases too long (for the adjustment you have your crimp die currently set at) will be overcrimed. This can cause a bulge in the case neck, or in the shoulder of the case.

At a guess, you have a few rounds that got bulged shoulders, enough so they won't go fully into the chamber. I have had this happen to me.

The field expedient is to give the forward assist a good wack or two, to force the action closed, and fire the round.

HOWEVER, BE AWARE THAT if the action does not close after using the forward assist, you are going to play hell getting that bad round out of the chamber. The AR simply has no way to exert much force on the charging handle (and its not good for the flimsy handle if you do). At this point, your best (and maybe only) option is to open the rifle,(if the carrier isn't far enough forward to hinge it open, push both pins and lift off the upper) and apply force to the rear of the bolt carrier (use wood), to get the bolt back. I have done this. Wasn't happy about it, but did get the rifle cleared. After a couple times doing it, I stopped trying to force the action shut on a bad round. Without doing that, they would usually extract via the normal pull on the charging handle.

FWIT, I took those bad rounds, and fired them through a Mini14. The gun fed them all, with a couple of failures to fully lock. A smack on the back of the op rod handle locked it shut, and they fired just fine.

 

[riverwalker76]

I'm sorry, but this does not make sense. The ejector does not "grab" anything.

Sorry, I didn't correctly state was I was trying to say. Sorry for the confusion. What I meant to say was that the case was stuck in the chamber, due to being bent, and in order to eject the round he is fighting the ejector.

When this happened to me it was due to a faulty depriming pin in my sizing die. I had removed the depriming pin to readjust it, and in doing so the sizing button on the depriming pin was slightly off center.

This caused the slightest error in my cartridges. Unfortunately, in my case, I had to go back and pull bullets on 200 Lapua .223 Match Brass.

After fixing the problem I have never had a problem. It was all due to the neck being slightly off center going into the chamber.

Also, forgot to ask ... are you using a JP Low Mass Bolt Carrier, or is it standard?

 

[higgite]

Sorry, I didn't correctly state was I was trying to say. Sorry for the confusion. What I meant to say was that the case was stuck in the chamber, due to being bent, and in order to eject the round he is fighting the ejector.

When this happened to me it was due to a faulty depriming pin in my sizing die. I had removed the depriming pin to readjust it, and in doing so the sizing button on the depriming pin was slightly off center.

This caused the slightest error in my cartridges. Unfortunately, in my case, I had to go back and pull bullets on 200 Lapua .223 Match Brass.

After fixing the problem I have never had a problem. It was all due to the neck being slightly off center going into the chamber.

I think you're getting the ejector mixed up with the extractor.

If an off center sizing button was the OP's problem, wouldn't it effect more than 3 out of a 1000 rounds? I'm thinking a couple pieces of brass somehow got through his QC routine and didn't get properly sized and/or trimmed. But I've been wrong before.

 

[arizona98tj]

1000 rounds through my M&P so far, three 'jams' for lack of a better term.

3 rounds out of 1000.

I fail to see how purchasing a box of 20 rounds and shooting them is going to prove much, if anything. Statistically, the chances of the OP having a problem during those 20 rounds are quite slim.

Every machine can malfunction. 3 rounds out of 1000 isn't bad....for shooting reloads. It would seem that several variables (not to mention the magazine) could account for 3 bad feeds out of 1000. Range pick up brass....I know shooters who leave their bad brass on the ground (at the range).

 

[riverwalker76]

Well, the OP seems to have abandoned his post!

I'm going to consider this topic dead until I hear back from him since it has been over a week without a word from him.