New AR-15: Frequent Double-Feeds

From Pat Rogers, owner of EAG Tactical:

Effective 01 Jan ’11 EAG will not permit the use of the following ammunition in our T&E/Loaner Guns:
ANY steel cased ammo
Q3131A
Additionally, if you bring the above ammunition to class and you have a weapons problem we will not loan you an EAG gun nor will we be able to work on your guns to get them running again. We spend way too much time on problems directly related to the above listed ammunition, and cannot afford to do it any more. It is not fair to other students nor to us. Bring a serviceable gun, sights, magazines and ammunition. Bringing a second gun is never a bad idea.
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Pat sees more rounds downrange every year than just about anybody on this board so he has a pretty good idea of what works and what doesn't. As has already been suggested, put the steel cased stuff on hold while you troubleshoot the gun.

Hey rainbow, don't be embarrassed. By reading online forums you'd think Colts never need cleaning, much less out of the box. Give that bad boy a good thorough cleaning, lube up the bolt and BCG contact points real nice, and see what happens. It still seems odd that that would be the culprit of double-feeding. So try the other pmag you have and whatever else is on hand and see what happens. Also note if the bad pmag has any cracks on the feed lips or something that could indicate it is compromised, causing it to release two rounds on accident.

Step 1: Read the manual that came with the gun

BCG = bolt carrier group

http://www.ar15.com/content/swat/keepitrunning.pdf

As the others have said, the first step now is to give the gun a good cleaning and then lube it properly. Take it to the range, mark your magazines, and see if the malfunctions still occur. If the misfeeds only show up on the mag each time, then you have found the problem. PMAG's are great mags, but Magpul does put out the occasional lemon.

with a brand New AR, I recommend the rifleman bring an assortment of magazines and good Quality, Full power Ammo (I use Lake City M855) for the first few hundred rounds.

The USMC tech manual notes that Carbon will seal the joints at the Barrel/Gas Block, and Gas Block/Gas Tube with the first few rounds.

Heavy Lube on the BCG (Bolt Carrier Group) is also called for, as 'New' = Stiff and Tight action. Many Manufacturers ship a rifle with a lube that is a better protectant than lubricant, so Cleaning and Lubing is a good idea.

If we 'stack' slightly weak Ammo (or just ammo with a less ideal pressure curve) with a slightly leaky gas block and a stiff action, we are almost always going to have a problem- usually Short Stroking.

Double Feeding is almost always, IMX, Magazine related. I can't think of a 'wrong' way to load an AR magazine, but it may be possible- as each round goes in, make sure it's going in and BACK (would shouldn't really make a difference) and give the mag tap against a hard surface on it back (primer side) to settle the rounds back in the magazine before loading it into the rifle (I do this pretty religiously, but I bet it really doesn't make a difference).

Having at least on other magazine would let one quickly see if the issue was the Mag- even if only one was to be found, I'd be surprised if no one at the range would let you borrow one for a string or two just to check your rifle- if no one on the line is shooting an AR, ask the RO.

http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/#performance

I looked at this and wasn't surprised at all in the results YMMV, but take a look !
Clearly this looks very much like a magazine issue.

Interesting.


Well, in that case, lube the bolt carrier assembly.

Liberally.

The mag in question is in fact a Magpul PMAG 30. Is there a "wrong way" to load a mag?

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sometimes giving a full mag a good rap/knock on something hard, or the bottom of your boot, etc. will help sort out any play...

FWIW, Ive got one PMAG that hates to load the first round but otherwise will run flawless after that. They are not infallible.

Warp said:

No.

Would you mind stopping with the straw man arguments/troll?

We have a guy who is new to the AR, who may well not have lubed it properly, who is experiencing a malfunction that is usually the fault of the magazine, who is using cheap Russian steel case ammo. I don't care who made the AR, the standard recommendation is going to be to lube the BCG, use decent ammo, and use GOOD mags (and a different mag than the one that was double feeding). No need to turn this into a stupid brand war.

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I'm new to the AR. Where do I go to find out the best lube and way to apply it? TIA

I'm new to the AR. Where do I go to find out the best lube and way to apply it? TIA

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Not to divert too much from the OP thread. BUt there's a lot of info out there about lube types and where to lube. For the most part, any good commercial lube product will suffice. Where you lube is more important. Lube the bolt and cam pin, and the gas key and the four rider contact points of the bolt carrier (where the carrier actually touches the receiver). A little bit of lube in the charging handle will also be good (underside is where the gas key is sliding back and forth, top side is where the handle will rub on the receiver when you manually charge. A drop here, a drop there, spread it around, when in doubt, drop of lube. Most importantly, just continue to do research and learn and draw some of your own conclusions. Have fun!

Haven't read the article yet, but the picture of the guy using the Vagasil bottle is pretty funny.

I'm a soon to be new AR owner too, so this has been a (somewhat) enlightening thread.

lynxlead said:

I'm new to the AR. Where do I go to find out the best lube and way to apply it? TIA

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Did you read this thread?

Link that was given previously in this thread:

http://www.ar15.com/content/swat/keepitrunning.pdf

RainbowBob,

It is possible to load any magazine incorrectly. If it feels wrong, it probably is wrong. Each round should lay flat and neat atop the other. While you do need to make sure any preservative applied by the factory is removed and the weapon properly lubed for best functioning, double feeds have only one source- the magazine. The magazine is bad, or the rounds are not loaded correctly. If the round isn't flat in the mag and firmly pushed to the rear so the bullet nose does not catch the edge of the mag when pushed down, there will be problems. If the bullets are inserted so they nose up, you will get double feeds.

As far a lubrication goes, a light coat of oil on the outside of the BCG (Bolt Carrier Group, or what your OM calls "bolt carrier assembly") and a few drops of oil into the carrier through the two vent holes is a good place to start. It is better to use a few drops too many than too few and experience will teach you how much you need to use.

Here are some threads to help you-

The following post is a good one, but a little on the overkill side. Use your best judgement
http://www.m4carbine.net/showthread.php?t=35490

It shows the use of cotton swabs appropriately, but never EVER use cotton swabs to clean out the gas tube. If the cotton comes off and gets stuck in teh tube, you'll be hating life. I've been shooting ARs for some years and have never used or needed a cotton swab for anything. Use common sense and keep your cleaning regimen simple

http://www.m4carbine.net/showthread.php?t=79448

AR MYTHS TO WATCH OUT FOR
While over-gassing is a real problem, it is not the source of all malfunctions. No matter what problem a shooter is having with their AR, someone will be along to blame it on over-gassing, even those over-gassing could not possibly induce.

Another myth is that the AR does not have a piston and operates by direct impingement. The fact is, the bolt of the AR is it's gas piston and Eugene Stoner states in his original patent application that the gas system is not a gas impingement system. If you want further references, let me know.

The BCG is not exposed to high temperature gases. By the time the gases reach the expansion chamber of the BCG, they have cooled quite a bit and pressures have dropped dramatically. You can test this for yourself- fire enough rounds at a steady pace until the gas block is too hot to touch, then immediately break open the action and extract the BCG. It will be barely warm enough to notice in most cases. The gas key might be a bit hot to the touch, however.

The gas pressure in the BCG does not push the bolt forward to assist in unlocking. To do so, the pressure in the BCG would have to be higher than the pressure in the chamber & bore. Anyone with even the simplest understanding of physics can see this is impossible.

Another myth is that the AR is not reliable or durable. History has proven this to be clearly untrue. Not only does the AR run reliably, it does so with less weight than most other rifles.

The AR is NOT a weapon's platform. Aircraft, tanks, vehicles, tripods, turrets and the like are weapon's platforms. The AR is a rifle, carbine, firearm, small arm, weapon......

There is nothing wrong with a rifle that needs a little attention. All forearms need some kind of preventive maintenance. Anyone who thinks otherwise is a fool. The AR does not need any kind of special or unusual care. In fact, it's needed PM is less than some very successful battle arms

Congratulations on your new rifle. With a little learning and some experience, you'll soon have your problems ironed out

Just want to weigh-in. A few years ago I bought a Colt Match HBAR before Obamas first election, for fear of not being able to get an AR after. I too thought the Colt would run anything, being a top shelf.

Unfortunately, my Colt will not run any of the 1000's of rounds of WOlf 223 that I bought then lol.

However, I did not have double feeding of live rounds, that does sound like a magazine issue. Instead, the fired cartridges were staying in in the chamber, unable to be extracted. I found out later about the lacquer coating on the wolf.

then rapped the mag on the palm of my hand and could feel everything just kind of bounce into place. This will become a habit.

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Good.

I do that with all magazines after loading, rifle or handgun. It ensures that the cartridges are seated properly against the rear of the mag, no bullet noses digging into the front of the mag and binding everything up.

The only feeding problems I've ever had with the AR were cheap or worn out magazines. Incidentally, the Promags you were advised against earlier in the thread have run just fine for me. I like their 42 rounders.

It's not that all promags are crap. It's just that their quality control is horrible.

jerkface11 said:

It's not that all promags are crap. It's just that their quality control is horrible.

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I have seen more than enough that I do not plan on ever paying money for a promag.

AR mags I would spend money on:

Magpul PMAG
USGI mags (not all aluminum mags are USGI!). I really like NHMTG specifically
Lancer L5 AWM
Troy Battlemag

I've got some Korean steel 30 rounders that work fine. I doubt you can get them anymore though.