out at the range a few days ago, and one of our highspeed low drag former seal dudes was telling us that an M4 can cook off with less then 300 rounds through it, now the most I have ever shot through mine was 7 mags as fast as I could, and she wasnt close to cooking off. Acctualy I have yet to see anything cook off and that includes firing ungodly amounts of saw and 240 rounds through those respective weapons but i figured I would ask you guys if you have ever seen a M4 cook off.

I personaly think it is poor trigger control.

I would have to agree with you on the trigger control.

I have fired wayyyyyy more than three hundred rapid fire without a cookoff on many occasions.

Maybe if you dumped 3 beta mags consecutively on FA........................no, I even doubt it then.

The M4 (or M16A2 or M16A1) can reach the 'cook off' point in as little as 140 rounds.  Now to get there in 140 rounds you have to be firing full-auto and switching magazines ASAP.  Now getting to the point does not mean you will be guaranteed a cook-off, just that it is possible.  

BTW this subject is covered in the Technical Manuals...

From what I have read, it's fairly hard to achieve cook-off with a semiauto. You need a full auto for that.

And you couldn't possibly get a cook-off with a M249 or M240, as those are open bolt...

the m4's we have are full auto ;)

Ok forgot that little detail on the 249/240 I will go smoke myself now

Quoted: From what I have read, it's fairly hard to achieve cook-off with a semiauto. You need a full auto for that. And you couldn't possibly get a cook-off with a M249 or M240, as those are open bolt...

Man I love this site. I learn something new everyday. I did not realize the M249 and M240 were open bolt MGs. Does the now-retired M60 fire from an open bolt?

Sorry for the hijack!

Theoretically, the chamber would have to melt your finger to the touch to be able to cook off a round.
I mean it would have to be insane hot, because if you look at any ammunition technical data, they usually state that direct heat in the amount of 1100 degrees or something is needed to cause the powder to ignite and start burning.

So, if we want to be fully accurate here we need to first get the specs on XM193 and direct heat, or M855, etc.


- rem

the ammo we use is green tip

remember in the summer it can get to 120 plus here also

I have some extremely experienced associates who dislike M4 handguards because they doin't allow heat out.  Rails are much more conducive to cooling.

Quoted: I have some extremely experienced associates who dislike M4 handguards because they doin't allow heat out.  Rails are much more conducive to cooling.

I wonder how effective the full wood furniture on my mauser is at dissipating heat then...

the reason the cooking off thing was even being discused was becuase we were doing bounding drills and he wanted us all to go to the high port when we moved, well everyone that wasnt a seal is use to having thier rifle at the low ready when they move, and he explained why he thinks the high port is better then the low ready.

It mostly comes down to a guy that has only seen one way and wants the world to do it that one way, refusing to listen to guys with as much if not more experance then him ;)

M-60 is open bolt, as is virtually every belt-fed gun with the exception of some HK's.  

M-16 cook-off?  I have not experienced one in +20K rounds of happiness.  Virtually impossible in semi-auto (your finger would fall off first).  

Sounds like an AD, of which I unfortunately have had the experience. Fortunately it was only the ceiling.  

Don't point your gun at anything you do not want destroyed.hock.gif

There was a write up in the Shotgun News about a year ago on Surefire's new can, and if I remember correctly they put about Fifety 30 rounders through an M4 to see if the can could take the abuse. It didn't cook off...... So I can imagine it would be pretty hard to do, just my $.02

- Clint

Oh, BTW I just wanted to post this smily  just haven't found the right reason......

Yes Cook Offs can happen.  I have seen it happen one time. This was not an AD.
The mechanical saftey was on and the rifle was slung in front of the shooter muzzle down
between his feet.  His hands were not on the weapon.  The outside temp was just over 100 deg
and humid. Many magazines had been fired in a very short period.

Quoted: Yes Cook Offs can happen.  I have seen it happen one time. This was not an AD. The mechanical saftey was on and the rifle was slung in front of the shooter muzzle down between his feet.  His hands were not on the weapon.  The outside temp was just over 100 deg and humid. Many magazines had been fired in a very short period.

That could be a cook off or a UD if the safety was facing inward and some of his kit rubbed it off and tripped the trigger.  Haven't seen that one yet, but I've heard of it.

Hay man - He sounds like he is trying to be COOL - ignore the Seal -
300 rounds could happen if it was full auto and  super duper hot - 300 rapid fire - maybe.
But this does not happen often - I have only seen 1 cook of in a gov issue m-16/m-4

As for the 240 249 - they are open bolt weapons.
But if the round did get stuck in the weapon and or if there is a malfunction and the bolt is locked forward so some reason - you could get  a cook off due to heat of barrel and brass being stuck in chamber.
--Saw that happen - guy opened the top and the brass popped in his face.
He was not being safe and facing his head in the other direction as taught.
--- He ended up a the Main Side Hospital at Camp Pen.

If you are on the range -Just wait a while and come back to it once it cools off.

Quoted: the reason the cooking off thing was even being discused was becuase we were doing bounding drills and he wanted us all to go to the high port when we moved, well everyone that wasnt a seal is use to having thier rifle at the low ready when they move, and he explained why he thinks the high port is better then the low ready. It mostly comes down to a guy that has only seen one way and wants the world to do it that one way, refusing to listen to guys with as much if not more experance then him ;)

DO NOT LISTEN TO THIS SEAL  CRAP ---  
USE THE LOW READY POSITION LIKE YOU HAVE BEEN TAUGHT YOUR WHOLE TIME INTHE CORPS.
TRAIN FOR COMBAT THE WAY YOU HAVE BEEN TAUGHT IN THE CORPS !!!!
DO NOT SECOND GUESS YOUR TRAINING

When bounding - just watch that your rifle does not sweep your buddies.

The rifle was rolled to the right, the saftey was facing away from his body.

Quoted: The rifle was rolled to the right, the saftey was facing away from his body.

Thanks, just something to be aware of.  I already know of 1 fatality from gear on a vest dropping the hammer.

Quoted: There was a write up in the Shotgun News about a year ago on Surefire's new can, and if I remember correctly they put about Fifety 30 rounders through an M4 to see if the can could take the abuse. It didn't cook off......

Any article that tells you it put 1,500 rounds through an M4 barrel in full-auto with no breaks (with or without suppressor) and didn't even reach cook-off is flat-out lying to you. Tests to destruction show the M4 barrel will melt, droop and burst at less than 600 rounds. Add the extra weight and heat created by a suppressor and it would happen even sooner. No offense; but you aren't doing anybody any favors by stating grossly inaccurate information relating to safety.

Cook off occurs in the AR-series of weapons when the chamber reached approximately 600F. You CAN reach this temperature firing semi-auto and you can also reach this temperature in as few as 140 rounds (as noted earlier). Here is the safety warning on that subject:

GROUND PRECAUTIONARY MESSAGE
ACALA #97-03
DATE: R 051413Z NOV 96
CLASSIFICATION: UNCLASSIFIED (1nn)
SUBJECT: GROUND PRECAUTIONARY MESSAGE (GPM), 97-03 5.56MM M4A1 CARBINE

1. DISTRIBUTION: {MENU} THIS IS A GROUND PRECAUTIONARY MESSAGE THAT HAS NOT BEEN TRANSMITTED TO SUBORDINATE UNITS. SOCOM COMMANDERS WILL IMMEDIATELY RETRANSMIT THIS MESSAGE TO ALL SUBORDINATE UNITS, ACTIVITIES
OR ELEMENTS AFFECTED OR CONCERNED. RETRANSMITTAL SHALL REFERENCE THIS MESSAGE. SOCOM COMMANDERS WILL VERIFY RECEIPT WHEN RETRANSMITTING THIS MESSAGE BY SENDING AN INFO COPY OF THE RETRANSMITTAL TO DIRECTOR,
TACOM-ACALA, AMSTA-AC-ASIR, ROCK ISLAND, IL.

2. PROBLEM DISCUSSION:

A. SUMMARY OF PROBLEM: SEVERAL INCIDENTS OF COOK-OFFS, IN AND OUT OF BATTERY, AS WELL AS BURST BARRELS, HAVE OCCURRED WITH THE 5.56MM M4A1 CARBINE. THESE INCIDENTS HAVE RESULTED IN INJURIES TO WEAPON USERS. THESE INCIDENTS RESULT FROM FIRING NUMEROUS ROUNDS WITHIN A SHORT AMOUNT OF TIME WITHOUT ADEQUATE COOLING.

(1) COOK-OFFS OCCUR WHEN A LIVE ROUND IS LEFT IN THE CHAMBER OR IN CONTACT WITH THE CHAMBER OF A HOT WEAPON AND HEATS TO THE POINT THAT THE PROPELLANT IS IGNITED.

(A) SUSTAINED FIRING OF THE M16 SERIES RIFLES OR M4 SERIES CARBINES WILL RAPIDLY RAISE THE TEMPERATURE OF THE BARREL TO A CRITICAL POINT.

(B) FIRING 140 ROUNDS, RAPIDLY AND CONTINUOUSLY, WILL RAISE THE TEMPERATURE OF THE BARREL TO THE COOK-OFF POINT. AT THIS TEMPERATURE, ANY LIVE ROUND REMAINING IN THE CHAMBER FOR ANY REASON MAY COOK-OFF (DETONATE) IN AS SHORT A PERIOD AS 10 SECONDS.

(C) WHEN THE WEAPON HAS REACHED THE COOK-OFF POINT (OR TEMPERATURE) A ROUND SHOULD NOT BE LEFT IN THE CHAMBER FOR ANY LENGTHY PERIOD OF TIME. THE WEAPON SHOULD BE CLEARED AND THE BOLT LOCKED TO THE REAR TO ALLOW COOL
DOWN.

(D) SUSTAINED RATE OF FIRE FOR THE M16 SERIES RIFLES AND M4 SERIES CARBINES IS 12-15 ROUNDS PER MINUTE. THIS IS THE ACTUAL RATE OF FIRE THAT A WEAPON CAN CONTINUE TO BE FIRED FOR AN Indefinite LENGTH OF TIME WITHOUT SERIOUS OVERHEATING.

(E) THE SUSTAINED RATE OF FIRE SHOULD NEVER BE EXCEEDED EXCEPT UNDER CIRCUMSTANCES OF EXTREME URGENCY. (NOTE: A HOT WEAPON TAKES APPROXIMATELY 30 MINUTES TO COOL TO AMBIENT TEMPERATURE CONDITIONS).

(F) THE USER'S MANUAL (TM 9-1005-319-10) FOR THE M16 SERIES RIFLE AND M4/M4A1 CARBINE STATES, "THAT IF A MISFIRE OCCURS IN A HOT WEAPON, REMOVE THE ROUND FAST (WITHIN TEN SECONDS). IF THE ROUND CANNOT BE REMOVED
WITHIN TEN SECONDS, REMOVE THE MAGAZINE FROM THE WEAPON, POINT THE WEAPON IN A SAFE DIRECTION AND WAIT FOR 15 MINUTES."

(G) CAUTION SHOULD BE TAKEN BY THE USERS TO KEEP THEIR FACE AWAY FROM THE EJECTION PORT WHILE CLEARING A HOT WEAPON.

(2) COOK-OFFS OUT OF BATTERY RESULT FROM A ROUND WHICH COOKS OFF WHEN THE BOLT IS NOT LOCKED OR A ROUND WHICH COOKS OFF AS THE USER IS TRYING TO CLEAR THE WEAPON.

(3) BURST BARRELS RESULT WHEN THE WEAPONS ARE FIRED UNDER VERY EXTREME FIRING SCHEDULES AND THE BARREL TEMPERATURE EXCEEDS 1360 DEGREES FAHRENHEIT. WHEN THE BARREL REACHES THESE EXTREME TEMPERATURES, THE BARREL STEEL WEAKENS TO THE POINT THAT THE HIGH PRESSURE GASES BURST THROUGH THE SIDE OF THE BARREL APPROXIMATELY 4 INCHES IN FRONT OF THE CHAMBER. THIS CONDITION CAN RESULT IN SERIOUS INJURY.

B. PARTS, ASSEMBLY, OR COMPONENTS TO BE INSPECTED: NA

3. USER ACTIONS. {MENU}

A. TASK OR INSPECTION SUSPENSE DATE (IF APPLICABLE): N/A

B. REPORTING COMPLIANCE SUSPENSE DATE: N/A

C. INSPECTION PROCEDURES: N/A

D. CORRECTION PROCEDURES: RANGE PERSONNEL AND USERS SHOULD AVOID EXCEEDING THE MAXIMUM AND SUSTAINED RATES OF FIRE DESCRIBED IN THE USER'S MANUAL FOR THE M16 SERIES RIFLES AND M4 SERIES CARBINE. USERS SHOULD BE TRAINED ON
THE CAUSES AND HAZARDS OF COOK-OFF. BETWEEN FIRING SCHEDULES, ADEQUATE WEAPON COOLING TIME SHOULD BE ALLOWED.

Yes, the M4A1 can cook off!  I had a cook off on night at Fort Campbell during a ambush drill.  Fired 6-7 mags of M885 as fast as I could.  Inserted fresh mag as cease fire was given and waiting the assualt order.  Weapon cooked off as the order was issued.  Now finger was off the trigger and selector was set on safe.  That's the reason way SOCOM issues a heavier barrel to ODAs to help prevent cook offs.  We have always taught muzzles down during movement drills, especially peel backs.  Now during peel backs you only fire one mag at a time full auto then fall back given the weapon time to cool.

CD

I find that order irritating.  If they spent as much time making the guns do what the soldiers want, instead of the other way around, this wouldn't be an issue.

Quoted: Quoted: the reason the cooking off thing was even being discused was becuase we were doing bounding drills and he wanted us all to go to the high port when we moved, well everyone that wasnt a seal is use to having thier rifle at the low ready when they move, and he explained why he thinks the high port is better then the low ready. It mostly comes down to a guy that has only seen one way and wants the world to do it that one way, refusing to listen to guys with as much if not more experance then him ;) DO NOT LISTEN TO THIS SEAL  CRAP ---   USE THE LOW READY POSITION LIKE YOU HAVE BEEN TAUGHT YOUR WHOLE TIME INTHE CORPS. TRAIN FOR COMBAT THE WAY YOU HAVE BEEN TAUGHT IN THE CORPS !!!! DO NOT SECOND GUESS YOUR TRAINING When bounding - just watch that your rifle does not sweep your buddies.

Dont worry I will. ;)
It is interesting about the cook off though, i was doubtfull it could happen,
thanks for the help guys  

Quoted: Quoted: I have some extremely experienced associates who dislike M4 handguards because they doin't allow heat out.  Rails are much more conducive to cooling. I wonder how effective the full wood furniture on my mauser is at dissipating heat then...

That I'd like to see!!!

A Mauser cooking off by being too hot from firing continuously.  

Quoted: Quoted: There was a write up in the Shotgun News about a year ago on Surefire's new can, and if I remember correctly they put about Fifety 30 rounders through an M4 to see if the can could take the abuse. It didn't cook off...... Any article that tells you it put 1,500 rounds through an M4 barrel in full-auto with no breaks (with or without suppressor) and didn't even reach cook-off is flat-out lying to you. Tests to destruction show the M4 barrel will melt, droop and burst at less than 600 rounds. Add the extra weight and heat created by a suppressor and it would happen even sooner. No offense; but you aren't doing anybody any favors by stating grossly inaccurate information relating to safety

Hmmmm....

Well then since I didn't contribute any pertanent information I retract my statement and offer this...- Clint

Technical Report, "Fire to Destruction Test of 5.56mm M4A1 Carbine and M16A2 Rifle Barrels, Final Report AMSTA-AR-ES-92-2, September 96, USA ARDEC, Rock Island, IL.  (Approved for Public Release, Distribution Unlimited)

"M16A2 number of rounds to destruction, 491.  Time to destruction 2 minutes 49 seconds.  Max barrel temp at destruction 1599 degrees F.

"M4A1 #1, 540 rounds (gunner ran out of ammo). 3 minutes (gunner ran out of ammo).  1712 degrees F (gunner ran out of ammo).

"M4A1 #2, 596 rounds.  3 minutes 32 seconds.  1639 degrees F."

.

Quoted: Hmmmm.... Well then since I didn't contribute any pertanent information I retract my statement and offer this... - Clint

Hey, I'm not trying to bust your balls but you posted information that could absolutely get somebody hurt if they relied on it. I'm pretty damn sure that Shotgun News never claimed that you could suddenly fire 1,500 rounds from an M4; but I'll be happy to direct my ire elsewhere if I am wrong. In the meantime, there isn't anything wrong with not commenting if you don't know what the fuck you are talking about and your advice might seriously injure or kill someone and that applies whether you write for Shotgun News or post on AR15.com.

Mr. Roberts I for one am not a liar, I only related what I read and if you only did a little research before you flamed me you would have seen for yourself that Surefire is the one that made the increadible claim that they put more than a 1500 rounds through a gun and did not have a cook off........

http://www.surefiresuppressors.com/suppressor_science_torture.html

Besides you make it seem as though I was throwing useless informaton out there into the world wide web for everyone on AR15.com to read and live by, because what I say goes..... Grow up, the original poster is a MARINE, who obviously has some AR-15 if not M16 experience! I doubt he'll use whatever I say as the deciding factor on cook offs.... You are right though I don't know what The Shotgun News claims but Surefire says that 1500 rounds went through an M4 without a cook off................................................ Flame On!!

- Clint

Quoted: Hay man - He sounds like he is trying to be COOL - ignore the Seal - 300 rounds could happen if it was full auto and  super duper hot - 300 rapid fire - maybe. But this does not happen often - I have only seen 1 cook of in a gov issue m-16/m-4 As for the 240 249 - they are open bolt weapons. But if the round did get stuck in the weapon and or if there is a malfunction and the bolt is locked forward so some reason - you could get  a cook off due to heat of barrel and brass being stuck in chamber. --Saw that happen - guy opened the top and the brass popped in his face. He was not being safe and facing his head in the other direction as taught. --- He ended up a the Main Side Hospital at Camp Pen. If you are on the range -Just wait a while and come back to it once it cools off.

glad to see someone knows what the hell their talkin about.  ive also seen a M240B cook off.  hot weapon jams, wont charge, opened the cover,  and round sent.  

I had an A2 cook off after 9 or 10 mags of 3rd burst as fast as I cold fire them.  

Dude, I was thinking the EXACT SAME THING.

If you haven't read books like "We Were Soldiers... Once and Young" (and others), and you are a weapons designer/manufacturer, then you are not understanding how the weapons will inevitably be used by soldiers in heavy combat situations. Imagine dozens (or hundreds) of enemy soldiers charging a line of 12 men in 3-6 foxholes. You can bet they will be dumping mags as fast as possible. Currently that is not a realistic battle climate, but still there have been heavy engagements in Iraq that I'm sure have pushed the average M16 and M4 beyond the stated *12 rounds per minute* firing limit (which seems utterly rediculous).

- rem

Quoted: I find that order irritating.  If they spent as much time making the guns do what the soldiers want, instead of the other way around, this wouldn't be an issue.

Quoted: Mr. Roberts I for one am not a liar, I only related what I read and if you only did a little research before you flamed me you would have seen for yourself that Surefire is the one that made the increadible claim that they put more than a 1500 rounds through a gun and did not have a cook off........ http://www.surefiresuppressors.com/suppressor_science_torture.html Besides you make it seem as though I was throwing useless informaton out there into the world wide web for everyone on AR15.com to read and live by, because what I say goes..... Grow up, the original poster is a MARINE, who obviously has some AR-15 if not M16 experience! I doubt he'll use whatever I say as the deciding factor on cook offs.... You are right though I don't know what The Shotgun News claims but Surefire says that 1500 rounds went through an M4 without a cook off................................................ Flame On!! - Clint

Quote from the article:

"We fired 1,500 rounds on full-auto as fast as we could stuff 30-round mags into the gun. We totally ruined the barrel, but the suppressor was barely even marked," Dueck said.

Obviously you overlooked that pretty significant point in your original post reference to the article. This probably means they had the weapon muzzle in front of a ballistic shield and were protected significantly from any barrel failure during rapid firing.


- rem

Quoted: Mr. Roberts I for one am not a liar, I only related what I read and if you only did a little research before you flamed me you would have seen for yourself that Surefire is the one that made the increadible claim that they put more than a 1500 rounds through a gun and did not have a cook off........ www.surefiresuppressors.com/suppressor_science_torture.html

Maybe you could point out where it says that; because I don't see a mention of them not reaching cook-off. In fact, the closest thing I can find is this statement:

"We fired 1,500 rounds on full-auto as fast as we could stuff 30-round mags into the gun. We totally ruined the barrel, but the suppressor was barely even marked," Dueck said.

Some important things to note about that comment are that they don't mention what profile of barrel (More mass handles more heat and shorter profiles droop less) or any of the test parameters.

Besides you make it seem as though I was throwing useless informaton out there into the world wide web for everyone on AR15.com to read and live by, because what I say goes.....

No, you were just throwing useless, incorrect information that would get most people injured if they tried to duplicate it. And even the secondhand information you did have, you didn't relay correctly.

I understand that a genntleman at the Colt factory took an M16 and several labcoat types to the range and proceeded to destroy said rifle by firing it until it exploded. I'm sure the same study has been done to cookoff research.

Keep this in mind. A thicker barrell will only slow the heat rise to the external surface. It will increase the cooling surface somewhat, but not more than fluting, per se. The reason heavier barrels are used is that they do not suffer degraded performance under heavy firing conditions so much as say a sporter profile.

Cookoffs happen, but it's not that often. I know one SFAUC instructor who says he saw them all the time, but I know BUDS instructors who have never seen them. I suppose it depends on where and when you are.