Correcting Common AR-15 Problems

Black AR-15 on white background with orange can of lubricant

The AR-15 rifle is a great rifle—America’s rifle—and a system with a well-deserved reputation for reliability. And that was not always so, and it is possible to ruin any design with poor maintenance and improper loads.

Black AR-15 on white background with orange can of lubricant
The first rule is good lubrication.

The use of the wrong type of powder by the arsenals caused quite a few problems in Vietnam, then the Army finally caught up with the problem.

The AR-15 is revered as a low-maintenance rifle and that is true when compared to what came before it. The black powder rifles once used by the Army had to be cleaned after every battle or every shot, otherwise black powder residue quickly rusted.

Corrosive salts in primed ammunition meant much the same for the M1 Garand and the bolt guns it replaced. The M1 carbine was the first true, low-maintenance rifle adopted by the U.S. Army and, within its limitations, the carbine did a great job. The original AR-15 with the proper ammunition was very reliable and did not require as much maintenance as the previous M-14, and it does require cleaning and lubrication, and occasionally parts replacement.

The AR 15 is popular, easy to use well and accurate. To keep it rolling, follow a few simple rules.

  • Keep the rifle clean to prevent eccentric wear.
  • Clean it as if your life depends on it. For some, the rifle is an emergency firearm, and your life may well depend on it. For many, the AR-15 is a hunting rifle. A tie-up ruins a hunt or an important rifle match.
  • The AR-15 operating mechanism, including the trigger group, bolt and chamber, must be cleaned and made free of powder ash and debris. That cleaning cannot be accomplished by simply spraying with an aerosol. You must remove the bolt and bolt carrier and wipe them with an oily rag.

Basic Cleaning Steps

  1. Dissemble the bolt carrier group.
  2. Carefully clean it. I formerly used an old toothbrush, although now I use purpose-designed cleaning tools.
  3. Scrub with a good powder solvent.
  4. Clean the rifle again.
    Be certain to clean the area between the bolt and the barrel in the locking lugs where carbon buildup is often significant. I use specialized gun-cleaning picks to make sure the rifle is clear of carbon deposits.



While the rifle may function (and function well) with a certain amount of carbon buildup, there is a difference between normal and eccentric wear. Normal wear results in a rifle that will last for many thousands of rounds. Eccentric wear, or uneven wear, begins cutting into the metal much quicker. If you have experienced a malfunction, then clean the rifle, doing a bang-up job. Next, look at the extractor spring, which may need to be replaced.

Poor Accuracy

Another problem is poor accuracy, and while not strictly a malfunction, the rifle is not operating at its peak. This is especially true if it once demonstrated good accuracy. The problem is almost always a fouled bore. I have yet to see a shot-out AR-15 barrel, and have seen ruined barrels.

Gray AR-15 Muzzle Brake on light gray background
A muzzle brake reduces recoil and protects the muzzle.

Clean with a good bore solvent, using wet and dry cloths, a bore bush, and plenty of elbow grease. Once you have cleaned the action and barrel, the rifle’s problem may be fixed. If not, you need to look for the real problem. A damaged muzzle may result in poor accuracy, particularly in a rifle with no muzzle brake. A good gunsmith can re-crown the barrel and restore accuracy. Poor-quality ammunition also results in bad accuracy.


A staple of the gun writer is to fire a magazine of mixed ammunition to confirm reliability. That is OK as far as it goes, as long as you remember the loadings and their position in the magazine if you do have a malfunction. And mixing quantities of ammunition is not always a good idea.

Boxes of wrapped ammunition
There is nothing better than ripping open a newly arrived carton of ammunition. Hornady ammunition will never give you a moment’s problem. It burns clean and provides excellent accuracy.

A staple of the gun writer is to fire a magazine of mixed ammunition to confirm reliability. That is OK as far as it goes, as long as you remember the loadings and their position in the magazine if you do have a malfunction. And mixing quantities of ammunition is not always a good idea.

  • Steel cases often are coated with a polymer finish, which gets hot and melt a bit on firing.
  • Steel-cased rounds seem to zip right through that mess, although brass does not always feed through a polymer-lined chamber.
  • Stick with one loading or the other for reliability.


Keep the gun lubricated. In the case of a rifle kept for defense or pest and predator control, a little lubricant is fine. You probably will only fire a few rounds.

  • If you are going for a long practice session at the range, keep the rifle wet.
  • If you fire 100 rounds or more, keep lubricating the bolt and cycling the action before you continue firing. That goes a long way toward maintaining function.

The Trigger Group

Another concern is the trigger group. The trigger sometimes becomes inconsistent, with a differing amount of force needed to break the sear. That is because the action has become dirty and powder or other grit is in the trigger action. I have seldom seen issues with a quality AR-15 and good ammunition; when I have, the culprit usually was poor lubrication (parts guns with improperly staked carrier keys and other problems are a headache).

Poor-Quality Magazines

Another source of problems is poor-quality magazines. Many magazines work just fine when new although if dropped, or even handled roughly (such as slamming into the magazine well), they warp, crack or bend. The result is poor feeding. Trash an offending magazine. Your life is worth more than the price of a new PMAG.

Gas Rings

Gas rings are simple to test and replace.

  • If you extend the bolt from the carrier group and place it on a desk or table, it should support the weight of the carrier group.
  • If not, change the gas rings.

With proper lubrication, cleaning, good-quality magazines and using proven ammunition, the AR-15 rifle is reliable.

Young man in a white shirt shooting an AR-15 with trees in the background
For fun shooting, keep the AR-15 lubed and maintained.

When problems occur, the concerns discussed are responsible for the lion’s share of difficulty.

What do you do to maintain your AR-15 in top condition, ready for self defense or the range? Share your thoughts in the comments section.


About the Author:

Bob Campbell

Bob Campbell’s primary qualification is a lifelong love of firearms, writing, and scholarship. He holds a degree in Criminal Justice but is an autodidact in matters important to his readers. Campbell considers unarmed skills the first line of defense and the handgun the last resort. (He gets it honest- his uncle Jerry Campbell is in the Boxer’s Hall of Fame.)

Campbell has authored well over 6,000 articles columns and reviews and fourteen books for major publishers including Gun Digest, Skyhorse and Paladin Press. Campbell served as a peace officer and security professional and has made hundreds of arrests and been injured on the job more than once.

He has written curriculum on the university level, served as a lead missionary, and is desperately in love with Joyce. He is training his grandchildren not to be snowflakes. At an age when many are thinking of retirement, Bob is working a 60-hour week and awaits being taken up in a whirlwind many years in the future.

Published in
Black Belt Magazine
Combat Handguns
Rifle Magazine
Gun Digest
Gun World
Tactical World
SWAT Magazine
American Gunsmith
Gun Tests Magazine
Women and Guns
The Journal Voice of American Law Enforcement
Police Magazine
Law Enforcement Technology
The Firearms Instructor
Tactical World
Concealed Carry Magazine
Concealed Carry Handguns

Books published

Holsters for Combat and Concealed Carry
The 1911 Automatic Pistol
The Handgun in Personal Defense
The Illustrated Guide to Handgun Skills
The Hunter and the Hunted
The Gun Digest Book of Personal Defense
The Gun Digest Book of the 1911
The Gun Digest Book of the 1911 second edition
Dealing with the Great Ammunition Shortage
Commando Gunsmithing
The Ultimate Book of Gunfighting
Preppers Guide to Rifles
Preppers Guide to Shotguns
The Accurate Handgun
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (30)

  1. I have specialized cleaning equipment but what I concern myself with when cleaning is the bolt carrier group, I field strip it and place them in a ultrasonic cleaner with a special carbon cleaner and heat it up and clean it for twenty four minutes.
    Take the parts out and blow them almost dry with compressed air and then put the parts in my casing dryer for one hour for about thirty minutes.
    Then I clean the bore with copper solvent then I use the carbon solvent and clean the gas tube and clean the locking lugs and recess with dental cotton rolls.
    Then I do detail cleaning on the bolt carrier group and give it a light coating of lubricant and call it good, until I go shooting before I start I open the rifle up take the bolt carrier group out and put three drops of FP10 down the carrier key then reassemble and insert a full magazine charge the weapon and start shooting.
    With this method I have had no failures except by a bad magazine.
    I own and shoot six MSR’so that I’ve built myself in calibers from. 223 wilde to. 458 SoCom.

  2. Polymer does not melt. Steel case ammunition does not expand and contract like brass when fired. Brass creates a gas seal that prevents fowling from blowing back into chamber. Steel case allows this fowling/ carbon buildup. Problems are experienced when swapping from steel case to brass. The brass expands in chamber that is coated with fowling/carbon causing it to stick and not extract. Stay with steel or brass don’t mix. Polymer and lacquer do not melt, that is a myth.

  3. I recently purchased an Anderson am 15 for 399 and even asking the sales man at point blank if I would be better off buying a Smith and Wesson at a higher price took it to the range properly lubed with Winchester. 223 ammo I got through 1 clip no issues since then I can’t get more than 5 rounds off without a extraction failure and the bolt tamping a live round I asked their armourer to look at it he says an extractor issue any suggestions other than a new bravo company extractor spring upgrade? That or just send it back to Anderson?

  4. two new hand built ars…worked fine for first 200 rounds then would eject and rechamber a live round but wouldn’t reset the trigger. Cleaned them both…no help. So I figure i’m not getting something clean enough. anyone have any ideas? Thanks

    1. Check your gas port on the barrel under the gas block, more than likely fouled. sounds like you are under gassed arising from powder fouling.
      30 yr USMC ….mos 0371. semper fi !!!

    2. This sounds like a trigger/disconnector problem. If the bolt retracts enough to eject the spent case and rechamber a new round, the hammer should have been cocked & locked.

      It is a good thing that it did not go full-auto on you! Take the upper receiver off, then check to see if the trigger/disconnector/sear are working properly. Be sure to avoid letting the hammer hit the front of the receiver’s trigger well. Manually cock the hammer both with the trigger fully depressed (to verify disconnector), and then with the trigger released (to verify the hammer/sear engagement works). If the hammer fails to catch, then something is amiss, and needs to be checked-out by a competent AR armorer.

  5. Think I pulled a major fumducker here.
    Took delivery of my new Anderson AR15 today. Fired it for the first time, took it home for cleaning.

    I qual’d on M16A1/2 thanks to that nice Mr. Reagan. Field stripping and cleaning was no problem.

    Then, and this is entirely my responsibility, I reinserted the bolt without the charging handle. It slid home with a very final sounding click and yes, it is locked in place.

    Is there an user-level drill for fixing this, or do I have to send it back out for service/repair?

    1. Open or remove the upper receiver, and push on the rear of the bolt carrier. The bolt carrier assembly should pop & slide right out.

  6. Well, there’s 5 dollars worth of “my 2 cents” in here-so I guess mine won’t hurt much. As an old Navy lifer (Gunners Mate), there ARE a few items I can’t help but get a little itchy about. “Keep it wet” being at the top of that list. Mostly because I’ve never seen anything oily that didn’t attract dirt and crud. Has anybody tried using Dri-slide for comparison? As an armorer I used to mix up powdered molybdenum disulfide and alcohol, and paint it on moving parts stuff that needed lube. The alcohol would quickly evaporate and leave a coating of moly that would actually bond to the metal, resulting in a nice thin, dry coat that performed well for a longer time than most commercial lube. It really worked well on the M-1/M-14’s and 1911 .45’s I had to keep working for the rifle/pistol team. One time I was at a match and discovered I’d left my “magic molly” back in the armory, and came up with a quick solution of Jim Beam (Otherwise known by us dingers as “Group-tite”) and some pencil lead from a few smashed pencils. Worked pretty damned good Drank the leftover too—so’s I could keep the “lead in MY pencil” hee hee.. Just kiddin’ boys-just kiddin”.
    Anyway, I wish some gun manufacturer would try some dry lubes for comparative effectiveness on AR’s.

  7. Learn before you attempt any repair!! Pins are directional, gas must be perfect or it won’t work right, etc, etc, to much to list!! Just trust me. You will cost yourself money and frustration tearing into it with no knowledge of how it functions!!! It’s actually a very amazing thing of metal beauty when you do learn it!!!

  8. I went through basic in 1972. Proper cleaning was not a suggestion but a direct order. I never had a failure of any sort when we were doing live fire and after being selected for an advanced weaponry class in which we got to shoot live fire twice as much as the rest of the company it still performed with no malfunctions through night firing, full auto, sniping, and hitting 1/2 size pop-up’s at 400 meters with consistency.
    The only malfunction I ever witnessed was when a buddy’s rifle jammed, due to lack of bolt lubrication, and the company armorer that day failed to bring any lube to the range. My DI got his hair cream out of his kit, lubed the bolt with it and the show went on.
    These were older M-16’s that had seen hundreds if not thousands of troops put thousands of rounds through them during training and I attribute their reliability to anal retentive cleaning.
    This was something I have carried over to my civilian life. To me it doesn’t make any difference if I shoot 10 or 500 rounds through any of my rifles they are field stripped and cleaned after my shooting session.
    Gun powder residue and carbon build up in a rifle’s barrel and if you just leave it rust can form under the residue. I am generous with oil for the bolt because I don’t know when I’m going back out and oil evaporates. I also take time to properly clean the star chamber, and all aspects of the bolt. Trigger group springs also get blasted with a mild solvent and re-lubricated.
    I have a 20 year old Bushmaster Varminiter that has only needed new gas rings, firing pin, and a main trigger spring. Normal wear and tear.
    I also have an Sig 516 and a Colt accurized H-Bar with a bull barrel, that have always performed flawlessly.
    To me, each to his own, it doesn’t matter if you have a $500 AR or a $2000 AR it deserves proper attention. Who knows, you might just need it someday for something other than punching paper and if you’ve done your job the rifle will too.

  9. Alot of armchair commandos here.

    Clean it as you like. But making claims it has to be clean to run is wrong. Saying its not as reliable as an AK is “WRONG”. Saying it has to be wet is wrong.

    Going to the range and shooting 50-100rnds isn’t a hard session on the gun. And saying you should lube it after every 100 rnds is wrong. If this is the case, maybe you should have it looked at.

    I run my guns into the 800rnd range before I feel guilty and break the bolt down, and clean the barrel, etc. Do I have feeding/reliability issues? None.

    I have used Synthetic motor oil, Froglube, CLP and grease. These are in essence machines, oil them like so and don’t worry about it. But know what your gun is capable of. Run it to failure and figure out why it stopped.

    Just stop thinking you have to have a spotless gun to run reliably thats a ridiculous statement.

    1. I do not think anyone is saying that the AR will fail if it is not kept spotless. Most of us that spent time in the military like to keep our guns extra clean because at one time our lives depended on it. Personaly every time I go out shooting my AR I clean it with the same attention to detail as if I had a drill sgt standing over my shoulder. Having a clean rifle makes me feel safe and happy I know it would probably fire if I cleaned it less but why take a chance?

  10. I’ve been shooting AR series rifles since the 1980’s, and have seen about every kind of malfunction you can imagine. They are great rifles, and I’ve used them in combat and would choose them over anything else. of course, that’s just my personal preference.

    But they do break from time to time. Extraction springs have been the biggest issue with me, and I’ve used Buffer Tech kits to beef all of mine up.

  11. I own 2 Colt M4’s (one I bought my wife so I didn’t have to share at the range). I’ve run about 2000 rounds through mine and have used some of the cheapest, dirty firing Russian crap one can buy and it fires better than brand new. Brand new the weapon was very tight and now fires like a champ. I clean the crap out of mine and have had one FTF (bad primer in cheap Russian ammo) and never a failure to feed or failure to eject. I just bought a set of stainless steel dental scraping tools for 7 bucks to make sure I can get into all the nooks-and-crannies also now and they are needed when firing the dirty 223 ammo that comes so gloriously cheap by the thousands. No free lunch though – my cleaning time doubles when firing the crap-ammo but the crap ammo allows me to shoot 200 to 500 rounds each week at my range. I clean very well and lubricate properly and no malfunctions to this point, but the Colts seem to have a nack for firing everything you put in it with no problems. Well done Colt!

  12. Yesterday, I took a “never before fired” AR-15 tot he range to site. It fired one round and then the brass stuck in the chamber. The gun shop thought it was one defective round, since the rest of the rounds cycled flawlessly.

    Because of this article, I will make sure that lubricant is not a factor the next time I take it to the range!

  13. We clean our AR’s after every range visit with a full teardown, inspection, and lube. We subscribe to the “sloppy wet” system and have never had any problems. The wife’s AR is a DPMS that tends to break gas rings. Neither I nor our local gunsmith knows why, so I now keep a supply on hand. Without a proper disassembly and inspection I would never know it had a broken gas ring.

  14. Re: AR is not designed for reliability. Hey Gordon, that’s a bold statement. Do you have any data to back that up, such as number of stoppages per thousand rounds? Why would the US Armed Forces use an unreliable weapon for 50 years?

  15. The AR/M16 platform was never designed for reliability. The blowback system is no close to reliable when compared to the AK platform. If more of them were made with the piston system then they would be.

  16. With all due respect, Larry, I have a Colt hat has never malfunctioned after several thousand rounds and an RGUNs upper that malfunctioned every 100 rounds until I polished the chamber with a 410 bore swab. A good AR against an M1 Garand? Good luck!

  17. Hey steve, I believe you meant to say daimondback fire arms that’s right
    up the street from keltech In florida. I personally did some research and just recently purchased a AR 15 pistol FDE 7.5 ”
    From everything I can tell it’s seems like a well build AR 15 For the price. I couldn’t tell you more due to I haven’t shot it yet, so I hope it shoots as good as it looks. Daimondback is a fairly new company so I believe they
    would put out a pretty good product which I believe is made in good old USA. Most ARs are great home defensive firearms just choose the right ammo. Good luck and have a blessed weekend.

  18. Bob –

    With all due respect, a flash-hider is not a muzzle-break (MB). the picture in the article is a FLASH-HIDER. A MB can function as a flash-hider, but its primary purpose is to reduce recoil at the expense of a much louder muzzle-blast.

    To me, a muzzle-break has no purpose on a .223/5.56 unless used in rapid/auto fire competition rifles. The .223/5.56 recoil is so slight that a MB is unwarranted, given how much more muzzle-blast returns to the shooters & those nearby. To shoot a rifle with a MB, indoors, without double hearing protection (plugs & muffs), is cause for serious, permanent hearing damage/loss.

    I see way too many sprayer & prayers shooting at the 25-yard INDOOR range with their decked-out AR’s, unloading their magazines as fast as they can. More than half have MB’s whose blast really annoys those around them. Their accuracy/precision at 25 yards is so poor that, to me, it is a waste of time & ammo, but hey, it is their weapon, ammo & time.

    Also, extractor springs cannot just be “looked at”. One must know his/her rifle to know that, properly functioning, the fired cases will extract/ eject into a neat pile. When failures to extract, or eject, or that “pile” changes location or gets bigger, both the extractor & ejector springs need to be changed. Special tools are available to properly & easily change the springs, extractor, ejector, & pins on the bolt.

    Based on your bio, it looks like you are primarily a handgunner, and may need to shoot YOUR AR more to experience worn-out barrel(s).

    I shoot NRA Highpower with the AR-15 Service & Match Rifles. We shoot hundreds of rounds between cleaning, but meticulously clean at least every 200-400 rounds with no problems. Barrel throats do erode between 3,000 – 5,000 rounds, depending on loads and if bullets are coated, enough to affect accuracy at 300+ yards. My Match Rifle has over 4,000 rounds fired through it without having to replace any springs. This tells me I am close to a “catastrophic” spring failure, and should replace them soon.

    The barrel has no sign of erosion when I inspect it through a borescope. As long as I see no significant signs of erosion, I am good to go until I see groups/scores open up at 300 & beyond.

    Continuous, rapid firing does the most damage to the entire rifle, especially the barrel.

    1. Hey Spacegunner. Correct on the flash hider. It’s a A2 Birdcage. I have a 10- year-old 24″ fluted flattop, 2-stage trigger, etc. that easily shoots hand load groups under 1/2 MOA at 100 and 200 yds. Deadly prairie dog gun. I broke that baby in the old way and have never overheated it and clean it meticulously after each outing and each night if we’re shooting prairie dogs. No malfunctions ever. I also have a XM-15 and it has a muzzle brake. It’s set up for CQB and only has a great quick acquisition sight and the brake…no fancy “furniture”. You are correct about minimal recoil of an AR but since I installed the brake, the muzzle jump has been virtually eliminated and that’s made for better times on the 3-gun range. Yup, it’s loud and requires plugs and muffs but the gun stays on target much better for faster follow-up shots. I don’t shoot it indoors. They’re great guns if you take care of them. Good luck shooting high-power competition!

  19. I have seen worn out M16A1 barrels. When kept in the training unit, they were tired rifles. It is not uncommon to see throat erosion after a few thousand rounds. After 5,000 many of them are unfit for service. It is why barrel replacements are not uncommon in military or police service.
    Good cleaning is a must.
    Keep a few spare parts around, those known for wearing out like gas rings, extractor springs (with rubber parts) and cotter pins.
    Some civilian AR15-type rifles allow the hammer nose to hit and hook on the pin. Early Colt’s were so fitted. Those trying to let the hammer down without simply pulling the trigger can hook the hammer nose on the pin.
    Those simple items, inexpensive items, will help keep you rifle working.
    Most failures I saw in the field were basic failures to clean.
    We had 125 M16A1 rifles that worked very well. Keep ’em clean.

  20. Well, With All Due Respect, to AR owners…
    I will never own one “Because” of reliability issues. I am reasonable sure there are those who own and stand firmly by their AR’s but again, reliability is my concern. The last three gun competition I was in there were 24 shooters. All but one shooter (me) had AR’s with 20rd mags for the rifle stages. Fourteen of the shooters were law officers. Not One Single Shooter, except myself, completed the rifle stages without a malfunction. As a result, only TWO of 23 other shooters had better times and hit percentages than I had. My rifle… M1 Garand, 30-06.

  21. Sir,
    thanks for reading!
    Only you can answer the question on your rifle. Keep it lubricated, feed it good ammunition in quality magazines and test it on the range.
    Isn’t Black Diamond made by Yankee Hill Machine? If so there is no company with a better reputation for quality and durability in parts.
    There are so many AR 15 rifles it is difficult to be familiar with each one, but your testing will tell the tale. I am pretty certain this is a Yankee Hill product and it isnt exactly an inexpensive rifle!


  22. I am new to the AR 15 platform but not to duty firearms. Handguns & shotguns yes… But the AR 15 came into vogue after I retired.

    I’ve carried mostly Smith & Wesson or Sig Sauer P226.

    I also know that by asking this question I’m going to get into the Ford verses Chevy verses Dodge response…

    Everyone will have their own personal choice here or preference… That is why there are Ford’s Chevy and Dodges in the marketplace and being sold.. Otherwise someone would be out of business.

    But I’ve bought a AR 15 made by Black Diamond firearms out of Florida.

    My research seems to say they are a good firearm /weapon manufacturer.

    But I know some AR 15’s also can run in the $1,500 or more range.

    Unfortunately I don’t have “a closet full of $$$ of cash laying around to spend… So budget is a concern.

    So my question is this…

    How is the. Black Diamond AR 15 for a home defender type weapon?


    Steve Cullen

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