The truth behind the recent M4 controversy

Yesterday I blogged about the M4 reliability controversy story that was originally reported by the Associated Press. At best the writer of the AP article exaggerated many the points. The leaked draft of the of the analysis of the Battle of Wanat reads quite differently.

The M4 Carbine

The AP infers that the barrels of many of the weapons were getting white hot. From the AP article:

The platoon-sized unit of U.S. soldiers and about two dozen Afghan troops was shooting back with such intensity the barrels on their weapons turned white hot.

There is only one reference to a gun getting white hot in the draft report, and it is a SAW not a M4 Carbine:

Specialist Bogar fired approximately six hundred rounds at a cyclic rate of fire from his SAW when that weapon became overheated, and eventually jammed the bolt forward. Specialist Stafford noted, “Bogar was still in our hole firing quite a bit. Then Bogar’s SAW jammed. Basically it just got way overheated, because he opened the feed tray cover and I remember him trying to get it open and it just looked like the bolt had welded itself inside the chamber. His barrel was just white hot.”

In fact, it is not even possible that an M4 barrel can heat up to the point of being white hot. M4 barrels are made from Alloy Steel 4150. The melting point of this steel is 1426 degrees Celsius. For steel to go white, it needs to be over 1400 degrees Celsius.

The Ground Precautionary Message ACALA #97-031, from November 1996, clearly states that if an M4 barrel reaches just 737 degrees Celcius, the barrel will be weaked to the point where burst.


You are not going to see an M4 barrel white hot because by that point it would have exploded!

The AP also infers that the M4 Carbine is designed to handle a high rate of fire

The high rate of fire appears to have put a number of weapons out of commission, even though the guns are tested and built to operate in extreme conditions.

This is also not true. From the Ground Precautionary Message[^1]:



No operator should empty more than 4 magazines rapidly. The AP quotes the draft report:

My weapon was overheating. I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn’t charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down.”

I sympathize with the solider and would not dare to presume to question his actions in combat. He did what he had to do in the heat of the moment, but I cannot think of any current weapon in the M4 class that can sustain continuous fire. To make such a weapon it would need to have a heavy quick change barrel and maybe also include a heat sink. I doubt any soldiers will want to trade in their M4 for a heavy automatic rifle.

Many thanks to Jay, aka. jdun1911, for his research into this controversy. He should get all the credit for this blog post.

UPDATE: I just want to clarify a point mentioned by commenters below. If the solider fired his 12 magazines evenly over a 30 minute period he should have had no overheating problems (assuming the Army GPM info is correct). What we do not know is the period of continuous fire. As Bram, who has seen combat, said “Time moves very differently while under fire. It’s impossible to judge how fast those soldiers were actually firing.”.

  1. I do not make a .mil link to the GPM but it is widely published on the internet. It can be read in full on The Firearm Blog. I did verify, on a .mil website, that this GPM does exist

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Mark

    As an addition to your interessting article:

    “Fire to Destruction Test of 5.56mm M4A1 Carbine and M16A2 Rifle Barrels”

    “External Barrel and Handguard Temperature of the 5.56mm M4 Carbine”

    “External Barrel Temperature of the M16A1 Rifle”

  • Matt Groom

    A good tip off that an article is bullshit can be attributed to the fact that it came from the AP. I don’t think I’ve ever read an AP article on any subject that wasn’t filled with political bias, hyperbole, factually flawed arguments, and grossly incorrect statements.

    The M-16/M-4 family get way too hot to handle long before they become too hot to shoot. When air moving through the handguards is enough to burn you when you move or when a breeze blows, you instinctively move your support hand to the lower receiver. When the lower become uncomfortably hot, you hold the magazine. By this point, you’re well aware that the rifle is hot as hell and it’s time to slow down or find a new weapon. I’ve seen them get glowing red when being shot three round burst off of sand bags (in training, at night) but I guarantee you that if you had to move, you wouldn’t be able to pick that rifle up and carry it without seriously burning yourself. It only took about two hours to cool off!

  • Nicely done Steve. I didn’t expect the follow up and that you took the time to run the story to ground is great work.

    • Solomon, thanks but Jay gets the credit for that, not me.

  • Thanks for the analysis and leaks. I’ve been discussing this with some friends, and some of them can not get past their experiences in Vietnam.

  • FWIW: The GPM is from November 1996, and not 2006. ACALA (US Army Armament and Chemical Acquisition and Logistics Activity) hasn’t existed for quite some time. Their name changed by 2000.

    • Daniel, thanks for that. It was a typo. It is referenced in a couple of Army newsletters in 1997.

  • ctr

    I spent a couple of hours last night reading the analysis and I was really impressed with the soldiers (and marines) who did everything they could after they got stuck in a big nasty.

  • Cypher09

    “My weapon was overheating. I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn’t charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down.”

    12 Mags * 30 Rounds = 360 Rounds. 360 Rounds / 30mins = 12 Rounds a Min.


    So why did this soldier’s weapon overheat to the point where he couldn’t pull back the charging handle?


    So if you shoot 12 – 15 rounds a min your weapon is able to properly function to the Indefinite number of 140 rounds?

    Sounds like the Ground Procurement Message needs a serious reevaluation, that or it’s about time to get our troops a new weapon system.

  • Tom

    First off, this site is great and I visit almost daily to get my dose of cool firearm news.

    However I am a little shocked by the response to a story on M4 failure reports. Accurate or not, I feel the firearm community runs to the defense of M4’s before troops as if it were a personal attack.

    AR15s have become dangerously symbolic of American rights. Just like the .45 1911. What I don’t like about that is people close their eyes, with almost a hatred, to anything that tries to diminish our beloved symbols.

    Did the M4s fail? How could they not? I’m sure AKs failed, radios, rockets, tents, helmet straps. Digging into news stories is a very good thing, just give stories that don’t include our beloved AR15s the same consideration. And always support giving our troops the best even if it’s not what we have in our safes.

  • Zach

    The soldier reports using 12 mags at half an hour into the fight. Assuming normal 30 round mags, that’s 360 rounds over 30 minutes, which equals only 12 rounds per minute. Per your quote above 12-15 rounds per minute is acceptable for indefinite sustained fire. Something doesn’t add up here!

    Two thoughts. First, maybe this solder had used several of those mags in just the preceding minute or two and overheated his M4 that way. Second, is it possible that conditions in Afghanistan are reducing the heat management of the rifle? High altitude means thinner air that doesn’t carry away as much heat. And if the rifle is coated in dust, that may form a heat barrier as well, trapping more heat in the barrel and keeping it from cooling at its normal rate.

    I think the M4 is generally a fine weapon, but perhaps they need to improve its heat capacity and cooling abilities for the current uses.

  • Bram

    I’ve been in combat, therefore take the first-hand accounts with a grain of salt. Time moves very differently while under fire. It’s impossible to judge how fast those soldiers were actually firing.

  • Lance

    Thats very good that both Steve and Jay busted threw this bias this artical had. Like I said it is pure polotics. Its one reason the military hasent replaced the M-16/M-4 is that it dose work in combat. And Yes it can bemisused in the heat of the monement. Hay if my rifle got too hot id use my canteen to cool it down if it got too hot to hold the hand guards.

    I dought you’ll hear much more about this artical on the offical news. I think they already know the Blogisphire would crak there complants wide open if they complained more about this incident.

    Do you agree Steve???

    • I can’t believe that you would post a comment that is so full of spelling and grammar mistakes. I feel embarrassed for you.

  • Indeed, it doesn’t take long for an M4/CAR-15/M16 to get too hot to handle. Like Matt said, it just takes a bit of clarity of mind to know when you need to slow the hell down, but a poorly trained soldier is often going to lack that clarity in combat, even low intensity battle. The reality is this weapon system is designed for accurate fire, not so much suppression. That’s what the SAWs, 240s and crew served weapons should be doing. Unfortunately, some battles go on for a long time and if you’re in a static position chances are there’s plenty of mags handy and plenty of fear of being over run to motivate getting lead down range even when you don’t have a good target.

  • Thank you for this! I caught the story on the nightly news, and cried bull-$*^t as soon as I heard it.

  • Martin

    Doesn’t anyone understand that the soldier in question used ‘white hot’ as euphemistic slang for;
    “really freakin hot”
    “too hot to safely handle”
    “at a temperature in excess of operating specifications”
    “so hot it it didn’t work anymore”

    On a personal note, I’ve never liked the thin military barrels for this very reason. They overheat too quickly. All my ARs I’ve ever owned have had heavy barrel.

  • Matt Groom

    @ Tom
    The National Ensign and the Federal Constitution are mere symbols of American rights, maybe we should throw them out, too!

    The AR-15 family of weapons can fail. Anything man made can break, and the AR-15 is no exception. Unfortunately, the term “best” is incredibly ambiguous. I suppose the most accurate way to define “best” is by determining that which is preferred by the majority of qualified experts. Considering the number of experienced, qualified professionals out there who carry the AR-15 personally, it makes the AR series of weapons a very strong contender for the position of “best” weapon’s system.

    While I might personally prefer an XCR in 6.8SPC, the vast, vast majority of others might prefer something else. This is also perplexing, because I don’t have an XCR in my safe, nor do I have a safe! I can’t afford such luxuries, but I do have three ARs. It is my feeling that if we put it to a vote, and all criteria were considered, including price, the AR-15 would be voted the “best” weapons system available in the world.

    Maybe Steve can put up a poll!

    • Matt, you acuallly bring up an interesting point. In theory they would need to fire a 6.8mm round less (greater stopping power). Less heat from lower rate of fire = longer period of time before overheating.

  • Bram has hit on something most have missed. Time is typically overestimated by witnesses, and the amount of overestimation increases with the amount of stress. I rather doubt the soldier in question was checking his watch, so his estimation of 30 minutes likely far exceeds the amount of time that actually elapsed.

  • jody

    the US military has lots of great equipment in their navy and air force, which are the real strength of a modern military anyway. but they also have lots of not so great stuff. as far as what the US army and marines have, the 5.56×45 weapons blow compared to what they could have. what is head scratching is the religious, fanatical attachment to this caliber. a force-wide change from this caliber to another one would cost less than a single F-22. probably even less than the budget for keeping one of the US navy’s one-too-many aircraft carriers in operation.

    it’s not much different than NASCAR having an iron clad committment to carburetor technology for delivering gasoline, going on 20 years after every other auto industry switched to widespread use of fuel injection. or GM sticking stubbornly to push rods, when everybody else went to cams decades ago.

    all data and all real world experience point toward the US forces replacing their existing rifles with a larger caliber, semi-automatic only rifle. yet they don’t only miss the opportunity to do this every single time there is an opportunity, they deliberately resist the change, like an NFL coach riding his bad quarterback choice all the way until the bitter end. it’s gotten to the point of being ridiculous. guys, it’s time to change the quarterback. just do it.

  • ctr

    I am pretty sure that whether they had 5.56 or 6.8 or *insert magic super caliber here* they would have found themselves in a similiar situation.

  • Thomas

    The problem is not entirely the weapon system, it is also fire discipline. The AR-15/M16/M4 family of weapons has always had heating problems when used as a bullet hose. The M16/M4 weapon system has range and stopping power limitations that tend to encourage troops to expend ammunition at an accelerated rate. The design of the weapon causes it to heat up quickly and the combination of the two make it difficult for the rifleman to handle after prolonged fire. As this is the weapon in use by the US military, it has to be trained for.

    The M240 has a quick change barrel system that if used properly, particularly with a splash of water during the change, allows the weapon to be fired virtually continuously until the crew runs out of ammo. That these weapons were failing from overheating is more of an indication that proper fire discipline was lacking than that the weapon design is flawed.

    I can’t fault the troops in this situation too much, though. From all reports, the situation was similar to the stand that the 7th Cavalry made at the Little Big Horn.

    As far as the new report goes, most news articles are approximately 15% fact and 90% inference [no, I did not make a math error].

  • Portalis

    But all of that is besides the point, Solders are having their M4s Jam up in the field… In their case the ‘field’ is a terrorist ridden death land, where having a reliable weapon is most important.

  • Lance

    Its dosnt surprise me that every time a report (false or true) comse about the Stoner system (M-16 and M-4) that theres always a small group who always wants a differnt rifle adopted imeditally. But they fail to say that all the other 5.56mm guns have simular problums and guns like the G-36 and Styer AUG which AR hatters champion all the time have the same issues with heat and jamming. They use too much plastic too. They melt not just jam unlike a M-16/M-4. So there is NOT a 5.56 rifle which never fails like some people claim all the time.

    As for a differnt caliber well 6.8 or 6.5 caliber would be ok…. BUT since the US military is part of NATO there wont be a snowball of a chance to adopt a new caliber outside of 5.56 NATO. The Europeans dont like BIG calibers and have hugged 5.56 closer than the US dose. They will NOT go for 6.8 or 6.5 in the next decade. With this said I aslo point out that US troops in Afghanistain have used other guns outside standerd issue like the M-14 which military brass has tried and tried over the 50 years to get rid of and failed to has made a comeback since 2001. But again it uses a NATO round… i.e. 7.62 NATO.

    The job of guarding a outpost in fixed postions is a job for a 7.62mm GPMG like a M-240 or M-60 anyway. Most other militaries have always but a belt fed in the crows nest/ guard tower anyway. I think with Obama and Bush have neglected Afghanistain and not issued enough GPMG and heavy M-2s for US Forces there.

    And finnaly as for the claim thatwe hug the AR too much and fast thats not true. I cited that its best we can have for a 5.56mm rife, BUT its been misused and the M-4 is being over used for perposes outside a carbines job. The USMC has M-16A4s and has not over used the M-4A1 and NO MARINES have made or had BIG issues with them.

  • Mike E


    Your comment about those wicked Europeans hugging to mouse calibers is, well, utter BS I’m afraid.

    Read some of the history around the the way the US drove NATO to first use an overpowered (for automatic rifle fire) 7.62×51 then a (underpowered) 5.56 round when after WW2 far better options and platforms were available.

    Have a look at the way the Aberdeen Testing Grounds crew and their “Not Invented Here” mentality outright lied about every competing caliber and its effectiveness along with falsifying test results.

    The classic example would be that post WW2 the British actually went right back to the drawing board, reviewed all the actual hard data around and came up with the EM-1 and EM-2 and a .280 round that for ACTUAL combat use would still be superior.

    The fact is the AR15/M16/M4 platform is over 40 years old, is STILL being tweaked to try and ramp up reliability and as has been demonstrated is a fine weapon just so long as you don’t stray from a pretty limited range of conditions/maintenance/cyclic rate/range etc etc etc.

  • rm

    Regardless of the details this is yet another indication of the fact that the standard arm (m4/M16xx) is inferior to many other arms in many respects.
    The DI system is dirty and hot.
    I am not surprised folks with AKs can sustain fire for a longer period of time.
    How many reports do we need to get a decent rifle? This has been happening for forty years.
    Give the soldiers the SCAR, IAR and the ultimax preferably in 6.5×39 and move on..

  • jdun1911


    All rifles heat up when doing prolong fire. It’s not a opinion is a fact. The AR is actually good at removing heat. The aluminum receiver and handguard acts like a giant heat sink.

    The M16A1 has a pencil barrel which heat up faster then a standard M4 barrel. It also has full auto capability. You rarely heard of M16A1 heat up in combat in Vietnam.

    The M240 is a machinegun, hence it has a quick change barrel. The AR isn’t a machinegun it is a rifle. The AR also weight a lot less and it is one of the reason why the Marines are going to adapt the IAR.

    The 5.56 has more then enough power to kill enemies at 1000 yards.



    You’re right. The only thing that would have made a difference was more troops on the ground. No magic calibers.

    Mike E,

    The AR15 is not being tweaked. It has been in a continuous cycle of updates. Tell me what new rifles is actually new? SCAR? AR18. ACR? AR18. G36? AR18. etc.

    All these so called new and improve rifles are updated versions of even older designs.

  • Lance


    I didnt say Europe made the NATO rounds I said once adopted they held onto them for a long period of time and seem to be fixed on it now.

    And you complant about the Stoner system, well name a 5.56 rifle without any troubles and is so superiour in your opinion. The M-16 has been better than most european weapons like the AR-70, L-85, AUG, G-36, FNC, FAMAS, and SiG 552. They all have james in combat too. Troops in afghanistain all say dust ruins everything. Soviet troops in the 1980s all reported there AK-74 would jam is not cleaned constantly.

    If you want to argue about a new caliber for the US military fine. Theres alot of new ideas there and even some I like as we. But simply saying another 5.56 weapon is key thats just ludicrise. They all act the same Mike.

  • jdun1911


    All firearms will jam on you. If you never experience a jam in X gun, then you haven’t been shooting enough. It’s not my opinion it is a fact.

    When you have 90% of all troops like their M16, that is something to behold because troops always complain about something.


    Heavy barrel really suck when you have to drag it for miles and miles in hot weather. Heavy barrel really really suck when your training doesn’t require a chair and a table.

  • Lance

    I know you hate M-16 RM

    But the SCAR is NOT a good weapon to replace anything. Its a regergatated FNC has too much plastic whic will melt in sastained fire and IS WAY TOO EXPSENSIVE. The butstock brakes too easy. And is too bulky and heavy for regular solders t carry. It passed SOCOM because some General wanted a SOCOM only gun and got money from FN to make one.

    I dont know why some guys think that if its European its somehow such a better gun. When troops of NATO armys say they can have simular problums.

    • Gentlemen, please keep on topic. This is not a Euro vs. US debate.

  • Lance

    Sorry Steve

    Well anyway I think that this debat on the Sunday article is done anyway.

    It was political bias and poor reporting. Which got exposed on the blogispire. If you love or hate the M-4 will be around in the Military for years to come and in Police use even longer.

  • rm

    I don’t hate the m16. I have an original colt ar15 sporter. It is great fun to shoot.
    It is not fun to clean. It is accepted that the DI is dirty and hot.
    The SCAR is not perfect and it is not just an fnc. The scar is being deployed and if it has problems they will fix them. I don’t care where they are designed. The m4/m16 have endless problems in tough combat conditions. Twelve mags in a firefight is not a lot. The SCAR performs better in harsh env tests than the m4.
    What the soldiers need are more iar type weapons designed for sustained high rates of fire and a decent round like 6.5×39.

  • Lance

    The SCAR actually hasnt been used by any major SOCOM units outside 1 unit of Rangers who are testing it. I know some units stay with M-4s and perfer it. It has relighablity issues with is plastic lower and stock.

    I want to leave this discusion with this lat thread. Steve wants us to talk about the article….. not M-4 vs XGun. last of topic comment. I hate to say thought no matter what gun the Government will play with it will be 5.56mm I bet you on it.

  • Lance

    The article is faulty so I also wouldnt trust its wrighting on that the troops rifle stoped after 12 mags. In the stress of combat you can miscount real easily. And Like I said the gun may have not been cleaned the day before and or not maintaind and armored right. There too many factors in the few incidents reported that the M-4 is to blame for occiasional jams.

  • prettypete

    Hey there, guys. Great exchange. I’ve seen my share of M16s in combat here in the Philippines and have seen men try to create walls of lead around them at unseen attackers. I’ve also taken video of veteran fighters fire and move with steady pop-pop-pop from M16s and one bam-bam-bam from a DM with an M14. In both cases, I’ve seen the rifles of these fighters get hot but not to the point of failure. In both cases, too, the men, me included-an unlucky kibitzer, survived. One phenom i’ve seen from guys fighting in Sulu and Basilan though, are more guys carrying 2nd M16s on their backs (they’ve probably never heard the statement, “two is one and one is none,” but i’m sure they’ve come to the same epiphany through experience. Many of those who can’t get extras carry all kinds of handguns from the ubiquitous 1911 to an assortment of 9mms and .38 caliber revolvers. Add to these the amazing array of bolos, machetes, knives, samurais, axes, and even ice picks as well as clubs and arnis sticks. War is hell and these guys show it. They may have M16 horror stories like bullets dropping out of overheated barrels and landing only a few meters ahead, plastic mags dropping out of the mag wells of hot guns, and hot guns whose barrels bend (!?!egads) but I’ve never seen them happen and neither have the guys telling me (seems it’s always a buddy). What I’ve seen a lot of are dirty guns from jungle ops and lots of M16s being rested on the ground or on top of boots (visions of blown off toes here…arghhh). Btw, mostly the US Spec Ops guys carry M4s here-but they’re not allowed into hot zones. Main Armed forces issue here is still the M16A1, though more and more US aid A2s are coming to the field.

    • prettypete, very interesting .

  • prettypete

    Thanks, Steve. And oh, the problem with M16A1s, A2s, and M4s here is that soldiers on the ground (and Marines and Policemen) can’t seem to get enough of them. And by my saying, “lots of M16s being rested on the ground or on top of boots (visions of blown off toes here…arghhh)…,” I meant M16s being rested this way, muzzle down. You know reporters, they go way overboard sometimes and the same with their editors, going after the sensational and the quote out of all context. What’s important is that the guys out in the field are confident in their rifle and in their ability to keep their rifles working. I’m praying for their safety as they get in harms way in our collective places.

  • Thomas


    “All rifles heat up when doing prolong fire. It’s not a opinion is a fact. The AR is actually good at removing heat. The aluminum receiver and handguard acts like a giant heat sink.

    The M16A1 has a pencil barrel which heat up faster then a standard M4 barrel. It also has full auto capability. You rarely heard of M16A1 heat up in combat in Vietnam.

    The M240 is a machinegun, hence it has a quick change barrel. The AR isn’t a machinegun it is a rifle. The AR also weight a lot less and it is one of the reason why the Marines are going to adapt the IAR.
    The 5.56 has more then enough power to kill enemies at 1000 yards.”

    Yes, all rifles heat up and have to dissipate that heat. In the case of the M16/M4, the forward hand is either on the plastic foreend or the metal lower receiver [those things that act as a “heat sink”], both of which get quite hot during prolonged fire. The M1 and M14 barrels and actions also got hot, but the operators hands were protected by wood, which insulates much better and the slower rate of fire of these weapons helped to keep the heating problem down. The early M16’s in Vietnam had significant heat problems. That was one of the reasons why the forward handguard was redesigned a couple of times. Then there is the cook-off problem that surfaced early with the M16 when it was used as a bullet hose. These problems have been around forever with the M16 and training has to take them into consideration.

    I have no idea what your point was concerning the M240. I stated that it was a machinegun and had quick change barrel capability, which should have prevented any of them from having a malfunction due to over heating. According to the article, it too sustained heat induced malfunctions. The IAR will serve as a Squad Automatic Weapon, a la the M14E2. That may or not work out. We’ll have to wait and see. The BAR was one of the best SAW’s in history. But it was big, heavy and had a small magazine capacity.

    A 22lr has enough power to kill enemies at 1000 yards. But you wouldn’t want to have to use one if your life depended upon it. The same is true of the 5.56mm. It is an adequate cartridge out to 450 yards, After that its effectiveness becomes iffy. It is usual for riflemen to routinely fire 2-3 rounds at a single target with the 5.56 to be sure of knocking it down.

    The M4 is what it is. It is an assault rifle that is light, easy to tote, and easy to maneuver in tight spaces. It is convenient for mounted troops and is generally adequate for the purpose for which it was designed. As in any design, there are trade-offs. The deficiencies of the system have to be understood and the weapon operated within tolerances.

  • Lance

    It seems in the M-16 is still popular in SE Asia. Im interested that M-16A1s are still standerd issue and main weapon of the Pillipino Army. I aslo intersting that US SOCOM forces there are uses a combo of M-4s and M-14DMRS NOT M-110s.

    Proves the M-14 has a good use still.

  • jdun1911

    SCAR has its own set of heat problems. The bottom rail is mounted in direct contact with the barrel and for some reason it is still consider free float. So what you have as someone stated “the world hottest gun”. The heat transfer to the bottom aluminum rail, which is good for barrel because take some heat out of it. However it is bad for the operator because it will burn the skin off your hand.

    Remember SCAR isn’t a new firearm design. It is a upgraded AR18 clone, just like any other new gun that is out there.

    90% of all US military troop in combat or not like their M16. No other rifle in the US military is more love by the troops then the M16. If there were rampant problems I don’t think you will see these kind of percentage.

    There is a disconnect between reality and what the mass media feed on the general public.


    Plastic mags dropping out of the mag wells is not due to heat. It is due to bad mag design, worn out magazine catch (they are after all A1), or operator error. My bet is operator error. 99.9% when the magazine drop unexpectedly is operator error. In high stress situation magazine are not seated property when doing a reload. This happen in all guns. To minimize this kind of error, some operators downgraded the round count in the magazine by one or two.

    Hot barrel do not bend they warp which has a very negative effect on accuracy.

    “Bullets dropping out of overheated barrels”, I don’t think I will touch on that. Whoever made the comment must be high on drugs.

  • jdun1911

    I must correct myself. The A1 barrel can bend if enough force is applied to it in the field. It is a pencil barrel after all. For some reason that was lost to me.


    The M16 is very popular in SE Asia. They might move away from it because of national pride with their home grown version.


    The metal lower receiver is made out of aluminum. Aluminum is very good at getting rid of heat in short notice. It is the same metal that computer heat sink used on the CPU. Place an aluminum foil in the oven. Heat it up. Take it out wait for a few seconds and it is cool to the touch.

    There are two version of M4. M4 and M4A1. The later is fully automatic and is use by Special Ops. Unless the M4 is doing continuously 3 rounds burst for suppression it is highly unlikely that it will reach the point of overheating.

    Quick change barrel only works when no one is shooting at you. You’re not going to change the barrel when everything is fluid.

    If the .22lr can kill at 1000 yard so does 5.56. Right? If that is the case why go for a heavy bullet other then to to satisfied the ego? Ever seen a guy got shot with 30mm cannon and still able to move. Still alive and fighting? In Somalia, Somalian fighters was able to take multi .50 caliber hits and keep on fighting.

    There is no magic bullet. The rule of thumb is you keep shooting until your opponent is dead. You can inflict fatal wounds but that doesn’t mean the guy going to stop trying to kill you. You can bet the bank on that

    There was a kid that was shot in the face with a .30 cal and live. The image is way way too graphic so I email to Steve and let him decide.

    22 hits, 17 of which in the Center of Mass with .40 Ranger STX bullets. Fatal wounds but the criminal was able to keep on fighting. I can list ton and ton of reports on magic bullets that failed.

    • jdun1911, yea … that is just too graphic!

      Thanks again for all your research you did for the blog post.

  • Lance

    So the Pillipina home grown M-16 I thought was a A1 anyway?

    And thats a good point M-16A2/4 and M-4s dont over heat as much due to its burst cam. Mabie the Army can take full auto off M-4A1s?

  • prettypete

    The M16A1 has been standard in the entire Armed Forces of the Philippines since the 70’s and had been manufactured locally, under license from Colt by Elitool (Elizalde Tool), which was suspected of being a crony front for President Marcos and was shut down shortly after the 1986 peaceful revolution. The production run was said to have been fulfilled anyway. But the sad thing was the entire plant was cannibalized and sold off like scrap and if rumors are to be believed, ransacked. Sad, really, considering that it was an essential part of national security. The local production of M16s in the Philippines is a distant memory at present. We have to rely on refurbishing, American aid and on costly imports for more M16/AR rifles.

    Oh, and Jdun1911, I get your point. The guys (who are all field men/fighters) telling me these stories, as I had said, heard the failure stories from buddies and so on but didn’t experience them first hand. So one takes these stories with a grain of salt, really.

    I remember hearing stories about rebel guerrillas down South in the 70s who had no fear of M16s but would cringe at the mere pops of Garands and M14s. But look at the rebels there now, they’d literally kill for M16s. I was talking to young guys in Mindanao who seemed to know their guns but none have ever heard of Thompsons (which was a status symbol up til the 70s) or M3 Greaseguns. As I said, the problem with M16s here is there aren’t enough of them.

    About the caliber issue, I remember some of my inebriated elders talking it up one night about the Japanese arms in in World War 2 and how some fellow guerrillas would pull out the .25 caliber bullets from their bullet wounds but then would praise the M1 carbine round for making the eyes pop off a Japanese enemy they shot. They never failed to belittle the Japanese .25 and praise everything American. That was, until the M16. What a quandary that must have been for them. When I showed them a 5.56×45 round, they tried to be polite, but after some gin, they’d start to liken it to the old Jap .25. Nothing like a .30 (I don’t know if they meant the -06 or the USM1C), they quipped, and reminded me of the God-like status of the .45. Again, as I look back at these stories, I couldn’t help but shake my head and cringe. I just bite my lip out of respect for my elders.

    I discussed in my article Jim Sullivan’s opinions on our problems with the M-4 carbine.

    Basically, the M-16 gas system is tuned to the 5.56 cartridge, which has a near-cylindrical brass case. This straight case is very sensitive to chamber clearance. During prolonged fire sessions, the barrel heats up and expand, squeezing the chamber. This reduces clearances and “grips” the cartridge case during extraction. The M-16 gas system gives enough time for the brass case to shrink (from firing’s pressure expansion) and allow extraction. However, when you get down to 14.5″ or less, you just don’t give the brass enough time to relax and shrink. Therefore, during extraction, it is still sticking to the chamber wall. With a shrunk, hot chamber, the problem is exacerbated.

    Colt used a combination of a heavy buffer and a bigger gas port to make it work during cold barrel operations, but the M-4 will quickly have failures to extract in a long firing session. The special forces generally don’t have a problem with this because they rarely get into a prolonged firing session, allowing them to get away with the 10.5″ barrel. The piston systems on the market do not really fix this problem, although POF’s heat-sink-barrel-nut does mitigate against this problem. I haven’t seen other vendors acknowledging this problem. [Maybe Colt’s IAR’s heat sink is a reflection of this.]

    According to Jim Sullivan, iirc, his ideal rifle cartridge is the Soviet 5.45×39, because its case design aids extraction, and because its longer bullet length gives it the accuracy lacking in 7.62×39. [7.62×39’s bullet is too short to adequately stabilize.] If you’re going to use a subgun or short barreled rifle, say against the Mongolian zombie horde, then 5.45×39 may be the way to go.

    • Kivaari

      I know this is 5 years old. But, the most used 7.62x39mm bullet I encountered were the Soviet style PS. The steel core bullet. If you stack one up next to a 147 gr. bullet used in the 7.62X51mm NATO they are almost visually identical. One of the best performing as to consistency of velocity I tested was the Chinese version. The ammo we can’t have anymore. It went across the chronograph within 7 FPS of the publicized 2350 FPS when fired from an SKS. AKs are slower thanks to the 16 inch tube.

  • Ted

    I think Lance is on the right path. I doubt anyone would argue against the contention that belt fed, true machine guns, are superior to any type of rifle, for defending fixed positions. Maybe even dredge up some 100 year old technology, and make them water cooled. Throw on a circulating pump, and a radiator, and you could probably make a trailer mounted machine gun capable of truly sustained fire. Obviously not something you could lug around on patrols, but perfect for fixed defense. I see no reason the same weapon should be expected to do both.

  • prettypete

    Great posts on the use of belt feds for fixed defense, Ted and Lance. I also thought about the water-cooled Browning .30’s, 7.92 Spandaus, and .303 Vickers while reading the posts. Just keep the bunkers tight and well protected from RPGs and grenades and make sure not to get outflanked.

    Excellent points and analysis you shared, too Jimmy W. I guess S&W are up to speed on this with their 5.45×39 M&P AR.

  • Steven S.Baum

    I am retired LEO and have owned and shot many M-4/AR platform firearms.I am only stating this from my perspective,that is I have never gotten an AR platform firearm to malfunction even with the thousands of rounds fired.I was NOT in a combat role and yes they were cleaned after use,but I had the luck to be around when there was LOTS of free/cheap 5.56 and I used 20 round mags [ all we had then ] to literally dump mag after mag with no failures.I am also of the opinion that if it were not for the NIH [ not invented here ] syndrome – we would all be using the 7.62 X 39 round.I believe it is a good compromise [ that THE name of the game = compromise ] with all rounds available in a EDC firearm,one that is man portable and THERE when needed.Thank you all for the great reading and all you input and knowledge.

  • El Duderino

    I have credentials/experience that form my opinion on this. I was an infantryman, later a tank crewman, for 6 years in the USMC. I served most of one of those years as a battalion range coach (rifle & pistol) and crew-served machinegun trainer.

    There really is nothing wrong with the M16/M4 family when used for its intended purposes. They are semi-automatic weapons with burst or full-auto capability. Contrast that with an M2 HB .50 machinegun which is a full-automatic weapon with single-shot capability. A very portable full-automatic/suppressive fire weapon that won’t easily overheat? Try an American M180 machine pistol in .22LR!

    With that said, rifles SHOULD NOT figure prominently in any defensive plan. When defending a base, you have the luxury of using weapon systems that don’t require a lot of mobility. M16/M4s and even M14s are just a step above pistols. Next are the GPMGs — M240s in 7.62mm in this case. M2 HBs and Mk19 grenade launchers come next. Throw in some 60mm or 81mm mortars — 155mm howitzers, MLRS vehicles, and dug-in Abrams tanks for a REAL firebase — and we’re talking about a good defense! The problem is these heavy weapons are seen as “too much” by civilian leadership and by extension top military leadership. We lose perspective as civilians because ARs seem like “big guns” but in the military world, they are small potatoes.

    Story along those lines: Near the end of my time in the USMC I was with a reserve tank unit. One of my fellow sergeants, who was a local yokel police officer, remarked he wished he could bring his Glock .40 to combat instead of the issue M9 9mm. I replied, straight-faced, “You’re going to be on a tank with a 120mm cannon, a .50 machinegun, and 2 M240s. We’ll have a couple M16s stowed in the turret too. If you’re down to a pistol — any pistol, we’re seriously #$*(&#!”

  • Lance

    Steve Baum you are right. For Law Enforcement the M-4 is the perfect patrol rifle and it will be used by Large Law Enforcement Agencys for decades to come. Like I told Steve I had friends who wehre in Iraq and used the M-4. Many guns where to hot from the sun and never even fired. He had to wear gloves to shoot it on a hot day in Baghdad. Other weapons like the G-36 and even AK-47s also have those problums too. The problum is a few solders who dont take care of there weapons I know men who serve in amny ways armed work in the US Military and Security who just dont care about there weapons. And poor tactics and lack of troops in Afghanistain.

    Blame President Obama for the bad firefights now. He isnt sending enough troop.

  • John

    IIRC current SF doctrine is to do several mag dumps to disengage. High rate of fire, lots of rounds, all as covering fire. That’s why SF wants the HK piston system. The Gas tube on m4/ARs can melt from the abuse.

    You can always piss on it, can’t you?

  • G3Ken

    Just came across this blog. Nice reading and a passionate & informed readership.

    It seems that some readers took the 12 magazines in 30 minutes comment and then assumed an irrational and unlikely scenario. Yes, twelve 30 round mags is 360 rounds and, if all facts are to be believed, it does work out to a 12 rds/min AVERAGE. That’s an average. Does anyone believe that the guy was firing one round every 5 seconds? You don’t because that’s what the argument implies. The 12-15 round per minute sustained rate assumes a slow fire, one round approximately every 5 seconds. At THAT rate, the rifle is designed to function indefinitely. The real world doesn’t work that way.

    Use another sports analogy. A running back carries the ball 20 times for 100 yards, a 5.0 yards per carry average. Pretty sweet, eh. Looking closer, you see that 19 of his carries total 22 yards and one is for a 78 yard touchdown. Do you assume that the guy had a great game or just a one great run? Averages can be deceptive.

  • Lance

    For SF use the HK416 now anyway. So talking about Spc Ops dosnt matter too much the Delt Force has already adopted and bought H&K416s. For the standerd infantry man a regular M-16A4 is just ideal for him or her.

  • Bill Watkins

    Very good article and comments, glad of referral from Strategy Page. Matt Groom’s comments on AP are precisely what I’ve said about those swine for years. In fact, I am going to quote Matt’s comments whenever I can! Good blog!

  • justanotherguy

    >The Europeans dont like BIG calibers and have hugged 5.56 closer than the US dose.
    Bah. You guys should never have turned down .280 british and the original version FALs which fired it post-WWII. It’s your fault we’re stuch with stocks of .3006/7.62mm weapons. The calibre is too big with too much of a kick. .280 FTW. (or EM2 bullpups, like less crap SA80s a few decades early ^.^).

  • Steven S.Baum

    I maintain that a WELL maintained M-4 or variant will do as its needed to do ,BUT that iof the NIH syndrome was not such a biggie we would have gone to the 7.62 X 38 LONG ago.Or a variant of that as it would have evolved from a cartridge that has been around MUCH lomnger than the 5.56.And if we all admit it,the 5.56 is MUCH easier to hump ammo for and if we needed a SHTF gun we would all be very happy with that caliber and rifle.Just KEEP IT CLEAN !!!!.

  • Bill Watkins

    As I recall, Brits were planning to go to a 26 caliber back in the early thirties and initial plan was for our newly designed M-1 to use same caliber. COS MacArthur said No, as we had warehouses of leftover ammo from WW I. Design changed to The Big Three Oh.

  • prettypete

    Great perspective, El. Semper Fi.

    Can’t help but remember a Philippine Army Major General in an IDPA match. He just borrowed one of his men’s 1911 and mags and scored badly. I was the safety officer and he whispered jokingly to me, “Oops, lousy score. Heck, I use 105s (howitzers) down in Mindanao, anyway.” Then he returned the 1911 and mags to his soldier and said, “Sarge, have that pistol checked.” That General hung around until the safety officer’s fun shoot and asked me if he could have another go at the course he shot badly. This time, he borrowed my gun, a DA/SA .45. He acquitted himself well enough the second time.

  • To check out some facts around the reliability and upgrades made to the M4, check out Col. Tamilio’s post at the PEO Soldier blog:

    • Kevin, thanks for the link.

  • Lance

    I look at the Colonels link and it seems to agree with my views on the Stoner system. And also hints at that the Army is being due to financial reasons as well as performance staying with the carbine. Agree Steve?

  • Jerm

    In looking at most testing done on the M4, as well as my personal experiences with it in Iraq is 4 things.

    1. Magazines. The GI mags are the biggest contributor to malfunctions in any m16 platform. Changing to a PMAG or CAA equivalent would fix most of the problems.

    2. Maintance is not done to the level it should be. Springs and gas rings are not being replaced as often as they should. CLP needs to go. It doesn’t clean, lubricate or protect. Pat Rogers is a huge proponent of SLip 2000 and I use it as well. The rifle stays lubricated for much longer and with less oil.

    3. Operating system. After going to a piston system I quickly saw the light. Direct Impingement is just too dirty. Does it work? Yes. Is it the best, cleanest and most reliable? No. I don’t care how someone says it, putting hot and dirty gasses in your upper are not the sane way to go. Heat causes expansion in metal and the carbon hardens up and creates more friction. Going to a piston system fixes by releasing all the gasses outside of the action and in turn allows for a lot less heat transfer. I tested it myself and after 1500 rounds on full auto, as fast as I could stuff rounds into he gun my bolt was still cold enough to hold in my hand and was clean. Testing was done with Wolf 5.56 55Gr out of an LWRCI M6A2. There were 0 malfunctions.

    4. The 62gr 5.56 NATO round has crappy terminal ballistics at best. I have patched up 1 to many people hit with that round that should have killed them (head shots) but found that the round had rode the bone structure and only caused minor tissue damage. Upgrading to a 75gr round leaving a barrel with a 1:7 twist would solve most of our problems and still meet the Geneva conventions. A better solution would be an upgrade in caliber like the 6.8 or 6.5 and ditch the 5.56 all together. I have a problem taking a round to combat that I can’t even legally hut deer with because of its wound pattern is not up to par.

    I’m not saying the M4 platform is a hunk of crap, it just needs an update. With new metal treatments and coatings online, it’s time for a change to the platform.

  • On Jerm’s point about the magazines, there is an improvement in the works. This summer, the Army’s PEO Soldier office implemented an improvement to the magazines for the M4 and M16 and have begun a fielding program to put new magazines into the hands of all Soldiers in the system. The “improved magazines,” as they are being called, have redesigned springs and followers that present the round to the weapon with much greater stability.

    You can learn more about this at:

  • Thomas

    We did a similar test as Jerm, but with a 9.25″ barreled POF Upper on an M-16A1. 1,000 rounds firing at 1,000 RPM, we used three Beta C Mags and Magpuls after that. Fired 1,000 rounds as fast as we could reload. ZERO malfuctions, ZERO cookoffs. Wow was it hot, but it handled it GREAT. POF has their act together. BTW, we have no affiliation.

    Regarding the 5.56, having seen what the good ol 55g does with a 1:12 twist, and the 62g in 1:7 to humans, I’ll take the 55g every time. Just devastaing. Same with the 5.45×39. Nasty, nasty round.

  • jeff r

    In a 2006 ambush in iraq i emptied three full 30 round mags in what seemed seconds, pretty much as fast as i could pull the trigger and change a mag. i also loosed 4 40mm HE grenades from my m203. time and rules go out the window when the bullets fly.

  • Mike N

    What does the piston vs direct gas argument have to do with barrel temperature? Put a few drums through an AK and watch the furniture catch on fire.

    Any closed bolt, air cooled weapon will have issues during sustained fire. Heck, even the open bolt machine guns require barrel changes to keep that up, and their barrels are normally made out of much better/heavier steel.

    As far as the 12 magazines in 30 minutes goes, do you really think that he fired all of his rounds evenly over that 30 minutes? Just burn through a couple of magazines rapid fire and see how long it takes for the barrel to cool down. Once it is hot, it doesn’t just magically cool down when you slow the rate of fire later.

    The fact is that the M4 is an excellent weapon as long as it is clean and used correctly. Having said that, it’s design makes it difficult and time consuming to clean. I personally prefer a few other designs like the SCAR, XCR, and I have high hopes for the new ACR.

    Is the M4 a POS? No. Do I think there is better our there? Yes.

    Disclaimer: I own several AR’s.

  • Lance

    Mike I agre with you 90%

    As far as other guns if Robinson XCR had a better trigger pull yes it might be better. But that FN scar plastic pos is not worth the powder to blow one up. And they charge over 2-3 grand for them!

  • Vernon Lemky

    Lance.How the Hell do you know the MK.16/MK.17 is prone to melting?It could be polymer you know?

  • Vernon Lemky

    oh sorry.. off topic

  • FWIW: The upper receiver on the SCAR is extruded aluminum. The lower receiver, buttstock, side rails, and some other parts are plastic.

  • Lance

    All the metal attachments are connected to the barrel and in fireing in full auto will over heat and melt/burn any thing holding the gun.

  • Lance,

    All rifles get hot when the user goes cyclic. US Army tests showed that the M4’s plastic handguards could run from just under 120F to 300F depending on the location after 280 rounds were fired. I haven’t seen results for the KAC M4 RAS.

    Even if you could magically isolate the handguards from touching the receiver and barrel, the radiated heat from the barrel will quickly make any handguard quite toasty. Even the wooden handguards and stocks of older rifle designs could get warm enough to char and smoke.

  • Lance

    OK Destroyer I can tell your a FN fan but now going to personal attacks. First I work with weapons do you? I didnt sat abything about multicam and im tired of you bame calling since you love you scar too much . So stop the name calling before you just jump into conclusions.

  • Destroyer

    Lance, i am a FN fan. so what? I am a former soldier and current armorer and gunsmith so i stick with the facts. I suggest you start doing the same instead of spouting off rumors and disinformation obtained from the bathroom wall of the world: the internet. The reason why i am commenting is because i like this site and enjoy the articles about the firearms. I don’t enjoy people just spouting garbage and when i find misinformation i will continue to refute those claims. I can tell you are a AR15 fan but i dont care. your comment about are commander in chief are also inappropriate. Blaming him for afghanistan when the problems arose moments after he got into office? really?

    Note: i am only citing facts. I wasn’t the one that was saying the Rangers didn’t have SCARs or multicam or that there were no rangers in afghanistan. Please think about what you are typing for the love of whatever makes you sane…

    • Destroyer, I send you an email but the email you put in appears to be fake or not working. The email was as follows:

      Hi Destroyer,

      I appreciate your contributions of your knowledge in the comments but
      I need to ask you to refrain from insulting other commenters.

      I am sure you know more than I do, and that is great, but just state
      your opinion, do not call someone you disagree with an idiot, moron or

      Building a community is hard work and it can easily collapse into
      endless arguments if everyone insults each other. Please refer to the
      comment policy (posted above the comment form).

      Kind regards,


  • Destroyer

    yeah i havent my email in a while steve, but that being said, ill tone it down. I don’t mean any disrespect on your blog and will find more respectful ways to address firearms information rumors/fallacies i may find.

  • Destroyer, thank you. The email I sent you bounced. The address does not exist.

  • Destroyer

    yeah i screwed up and used a cancelled email address instead of my new hotmail one, which works.

  • bullzebub

    my thoughts… if they weren’t actually surrounded they failed to move. and.. .sustained fire? it seems like it was somewhat poorly trained troops. i mean… if you are going to make the bad guy hunker down you don’t actually need more than 2-3 shots a seconds.

    and the comment about “needing 2-3 shots to make sure he is dead” id say that’s true for all calibers … even .50 BMG. why? you cant really be sure you made a lethal hit. not even on ranges under 50 yards. especially when the adrenaline is pumping though your veins.

    and about replacing the ar15 platform…. sure. it has its problems. like reliability. but the great upside with it is that’s it so damn easy to upgrade. just slap a monolithic upper with gas system on it and you have fixed most problems… and this can be done gradually. and that’s good because you don’t have to retrain people on a new system, don’t have to replace all at once and can easy evaluate the system.

  • Travis

    Typical media. Probably just embellishing events to make the article more “entertaining” to the average person who doesn’t know anything about the functions of a firearm beyond what they’ve seen in a Stallone or Schwarzenegger movie.

  • Yalien619

    This is why the US Gov needs to switch over to a piston system instead of the regular gas blow back, they are not only more reliable in varying environments, but will help with the “over heating” of rifles. As a former soldier and NCO and proud veteran of the 101st DIV 2/506th BN, and having fought in both theaters, I have first hand experience with the M4 and its shortcomings. Its a fun plinking or target/range rifle but that is about the extent on it. The round is far to small (never shoot a large caliber man with a small caliber bullet) and there is a lot of ?’s remaining on the reliability