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Posted: 7/13/2005 5:53:54 AM EDT
These barrels were tested to destruction. I contacted the testing company directly and found the original intel on the actual test procedure was in error.Actually it was not the barrels that were being tested. The barrels were part a test of another component but the barrel destruction as a side effect.
There are a lot of threads here on barrels, barrel life, how tough are barrels etc etc etc. So I thought you guys might find this interesting. Their test procedure was pretty simple. The uppers were mounted on M16 rifles and simply shot on full auto for 200 rounds. The upper was then put in a rack and allowed to cool enough that a bore snake could be run up it and then the firing commenced again. The barrels were not completely cooled, but enough they could be swabbed out. Failures were due to excessive heat. Sorry for the initial confusion on the exact test procedure. On average the barrels gave up the ghost between 18,000 and 21,000 rounds of full auto fire. In cases were the barrel did not let go the barrel was totally roached with no throat for 2-4 inches and rifling missing in other parts of the bore. How long will your barrel last with normal shooting and cleaning? This should set some minds at ease. These are not COLT barrels. The barrels are DPMS 1:9 4140 steel. I would say DPMS makes a damn good barrel! What am I trying to prove? Really nothing just FYI and adding some real world info.    Denny |
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Posted: 7/13/2005 5:59:36 AM EDT
[#1]
Wow, cool.you would have to figure with continues full auto fire the heat played a bigger factor in falure then it would in normal firing cooling firing situations, they probably would have went alot farther.
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Posted: 7/13/2005 6:01:31 AM EDT
[#2]
I read somewhere that a bbl could only go like 3 or 4 hundred somodd round straight full auto mag dumps until it blew... Does this debunk that?
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Posted: 7/13/2005 6:03:03 AM EDT
[#3]
Hey, thanks for sharing, cool pics. Now I have not tried it, but my understanding is that you can pop a barrel with way less then 1,000 rounds. There must have been long cool down periods during this testing, like say overnight?
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Posted: 7/13/2005 6:04:34 AM EDT
[#4]
Were these barrels chrome lined?
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Posted: 7/13/2005 6:04:57 AM EDT
[#5]
Note to self, use HBARS when shooting 21,000 rounds on full auto.
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Posted: 7/13/2005 6:11:33 AM EDT
[#6]
I would say this somewhat debunks that. That is why I posted this. Time for the myths to stop and do a reality check. The barrels were not chrome lined, just rack grade DPMS 1:9 Barrels. Yes, the firing was continuous full auto with just cooling and cleaning breaks to run the bore snake and add lube to keep the gun running. Denny |
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Posted: 7/13/2005 6:21:28 AM EDT
[#7]
How dangerous was the test? Did any shooter or bystander get injured?
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Posted: 7/13/2005 6:23:13 AM EDT
[#8]
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Posted: 7/13/2005 6:23:33 AM EDT
[#9]
Some people have really cool jobs!
Spooky |
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Posted: 7/13/2005 6:25:07 AM EDT
[#10]
Tests like this are preformed all the time by people who are experts at this sort of thing. All safety precautions are in place. The guns are shielded so the operator cannot be injured. I would strongly suggest you don't try this on your own  Denny |
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Posted: 7/13/2005 6:25:25 AM EDT
[#11]
 very impressive. |
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Posted: 7/13/2005 6:26:59 AM EDT
[#12]
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Posted: 7/13/2005 6:29:32 AM EDT
[#13]
Not the poor bastards loading the magazines  Denny |
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Posted: 7/13/2005 6:29:57 AM EDT
[#14]
I'll volunteer my trigger finger for a couple thousand rounds on full auto.  I've never seen this kind of testing done. How were these rifles fed? I can't imagine someone swapping mags every 30 rounds. |
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Posted: 7/13/2005 6:32:34 AM EDT
[#15]
Hay, those FSBs have bayonet lugs on them? I could use those.
 Damn, I love destructive testing and its results. 
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Posted: 7/13/2005 6:34:17 AM EDT
[#16]
So it looks like the barrels heated up, bent, and the round then KB the barrel because it could not exit. Where these chrome lined? Would that even matter? |
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Posted: 7/13/2005 6:36:15 AM EDT
[#17]
Anybody remember that link to one of the articles from one of the gunrags? I think it's on Davidsons-they claimed that a Colt barrel was having problems after, I think, 10k rounds of semi automatic fire over a day or two. I always thought that seemed kind of low. The Army report linked to above indicates that two military M4 barrels both failed after less than 600 rounds of continuous full auto fire. |
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Posted: 7/13/2005 6:36:52 AM EDT
[#18]
Cooling times were enough to allow cleaning and lubing procedures to be performed safely. None of the barrels were allowed to cool completely. As I stated in the original post this was NOT a barrel test per se, it was a test of another component and the barrels were just a side effect. Any body need some slightly used front sights Denny Denny |
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Posted: 7/13/2005 6:38:41 AM EDT
[#19]
Send 'em.
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Posted: 7/13/2005 6:40:02 AM EDT
[#20]
In the Government test more then 500 round were fired in less then 4 minutes to get the M4A1 barrels to blow. That is a firing rate exceeding 125 rounds per minute. To reach 125 rounds a minute you have to change 30 round mags every 15 seconds.
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Posted: 7/13/2005 6:40:25 AM EDT
[#21]
The M4 rifles tested in that link deconstructed at ~590 rounds of continuous full-auto fire. Testing done by Rock Island Arsenal in 1996. Interesting comparison of tests, to say the least.  Notice the points of failure both on this test and on Denny's. This lead to the development of the M4 SOCOM barrel. . |
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Posted: 7/13/2005 6:40:49 AM EDT
[#22]
Heat is what killed the barrels, very, very excessive heat. The barrels simply got so hot they went molten and could not handle the pressure and ruptured. I wish I could get some good shots of the throats and bores but I just don't have the time to set it all up with the camera. Denny |
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Posted: 7/13/2005 6:49:26 AM EDT
[#23]
Link to the Colt Article: www.galleryofguns.com/shootingtimes/Articles/DisplayArticles.asp?ID=1205
Thanks for the pics Denny, pretty neat. |
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Posted: 7/13/2005 6:50:31 AM EDT
[#24]
That would be "CONTINUOUS" fire. So in reality, this "non-test" doesn't "debunk" any myth. It just starts a new one. A myth that says " My cheapo DPMS M-4 barrel will last around 20k in continuous full auto fire". Which is not true. |
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Posted: 7/13/2005 6:56:10 AM EDT
[#25]
I dont think it starts a myth. It in a way demonstrates the life of a barrel. If those barrels under those conditions did not KB until 20,00 rounds, the barrel life of an average plinker/range rifle will outlast any shooters life. |
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Posted: 7/13/2005 6:56:37 AM EDT
[#26]
That was a pretty cool test, 10,000 rounds. And yes the throat was damaged, and the bore was not chromed, and the barrel was a 1/9. What was it, last year Winchester did some testing on the 223 WSSM and found that a chromed bore doubled barrel life? There was also a military test conducted in the 1980's that showed the 1/7 twist barrel lost accuracy rapidly, like at 6,000 rounds, while the 1/12 barrels were more accurate at something like 20,000 rounds then they were at the start of the test (all memory here). |
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Posted: 7/13/2005 6:56:48 AM EDT
[#27]
Where is MarkM with a comment how the barrels failed because they are 1:9 tiwst and a 1:7 twist would not have failed?
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Posted: 7/13/2005 6:58:25 AM EDT
[#28]
FeedingCannibal wrote: "Notice the points of failure both on this test and on Denny's. This lead to the development of the M4 SOCOM barrel."
Feeding, this is somewhat tangential, but are you saying there's a difference between the "regular" M4 carbine barrel and this "M4 SOCOM" barrel that you mention? Could you please give me more info about the M4 SOCOM barrel? Do you have detailed specs on it? Pictures? Links? Thanks. John |
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Posted: 7/13/2005 6:59:43 AM EDT
[#29]
Do you always believe what the Government tells you? |
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Posted: 7/13/2005 7:02:16 AM EDT
[#30]
Just read the testing method, mags were changed about every 10 seconds. |
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Posted: 7/13/2005 7:02:49 AM EDT
[#31]
I could be wrong, but I think the SOCOM barrel is an HBAR, making it much more rugged than the profiled barrel. Here is a pic of some used SOCOM barrels 
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Posted: 7/13/2005 7:03:05 AM EDT
[#32]
No, this is the SHOW ME STATE. |
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Posted: 7/13/2005 7:04:24 AM EDT
[#33]
Not sure it should be called a HBAR, but the now standard M4A1 barrel is much larger in diameter under the guards. |
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Posted: 7/13/2005 7:07:48 AM EDT
[#34]
A HBAR in the civilian world is different from a SOCOM barrel. |
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Posted: 7/13/2005 7:10:56 AM EDT
[#35]
The barrels were fired 200 round cotinuous full auto and then allowed to cool enough to run a bore snake and lube. Then fired another 200 rounds and the cleaning/cooling procedure was followed again and again and again until the barrel failed. Denny |
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Posted: 7/13/2005 7:10:57 AM EDT
[#36]
When I went out shootin last Sunday, my dad tagged along cuz hed never shot anything like an AR. He accidentally grabbed the barrel and burned his hand. He was saying the barrel was getting too hot and that we should stop shooting it for a while. at that point wed only put about 100 rounds through it over the course of 30 minutes. I guess there wasnt much to worry about >=)
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Posted: 7/13/2005 7:14:00 AM EDT
[#37]
There was an M16 16" Hbar in the batch. I did not grab it to photo was it was not spectacular. The barrel was not ruptured. The throat and bore were however ..........gone.
Denny |
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Posted: 7/13/2005 7:14:18 AM EDT
[#38]
Agreed. |
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Posted: 7/13/2005 7:17:18 AM EDT
[#39]
.
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Posted: 7/13/2005 7:17:49 AM EDT
[#40]
double tap
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Posted: 7/13/2005 7:18:25 AM EDT
[#41]
That's some crazy Bump Firing and such, CLEATUS!
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Posted: 7/13/2005 7:20:56 AM EDT
[#42]
Wow, thanks.
How did the gas tubes hold up? |
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Posted: 7/13/2005 7:23:03 AM EDT
[#43]
1)It was an unlined Match H-Bar 2)They were cooking it pretty good, 10,000 rounds in one day. |
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Posted: 7/13/2005 9:50:56 AM EDT
[#44]
according to some here impossible..colt is perfect. eta sorry just a little cranky today 
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Posted: 7/13/2005 9:52:03 AM EDT
[#45]
It was 10,000rds over two days (still a pretty heavy firing schedule) and the issue was the throat of the barrel wore out right at the point where the ogive of the round they were using (PMC IIRC) contacted it. They finished the test by switching to a round with a different ogive and accuracy returned. Also, this was not a test to destruction. It was just a test where the rifle started showing unacceptable accuracy. |
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Posted: 7/13/2005 9:53:27 AM EDT
[#46]
Not ME, BABY! I'm No Proponent of 1:7! It should be BANNED! |
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Posted: 7/13/2005 10:04:22 AM EDT
[#47]
I wonder if the results would have been a bit different if the barrels had been chrome lined & made of 4150 steel?
BTW, markm... your this & that should be "banned" joke is way old and not funny anymore. Get some new material. 
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Posted: 7/13/2005 11:21:43 AM EDT
[#48]
Who said they were the same. The SOCOM is an HBAR |
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Posted: 7/13/2005 11:33:25 AM EDT
[#49]
Which has long made me wonder why a pencil or profiled barrel would be put on an automatic weapon, or even a semi weapon that will be shot for extended durations. Diemaco seems to know better and includes HBAR's on their carbines because of their "increased thermal mass and higher rigidity" The obession some people have with barrels profiled down to the diameter of a mcdonalds straw (courtesy of MarkM) to save a few ounces is baffling. Obviously there is a problem with profiled barrels and high stress, which is the reason the SOCOM barrel exists at all I suppose for a civilian it doesnt much matter since they wont ever subject their weapon to that kinda of abuse in one sitting under normal circumstances
This information will come in handy when some claims 4140 steel is cheap and not durable. 18k rounds sounds plenty durable |
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Posted: 7/13/2005 11:43:21 AM EDT
[#50]
The military used pencil profile barrells on rifles and carbines for decades. AK-74's have pencil profile barrels.
The simple fact is when your basic combat load is 310 rounds, it is hard to cook one unless you dump it all at once. I have abused unlined M-16A1's with only chromed chambers (120 rounds full auto, 50-50 ball-tracer) as fast as I could change mags laid out on the ground by my left foot and the barrel guaged fine afterward. The real reason the military made it heavier from the front site forward is to make it a better crow bar because people were bending barrels using them to stretch cots and other stupid shit.. If they wanted to help the thermal characteristics, they would have made it heavier under the handguards and kept it light profile on the front like an M-14 match barrel. Believe me, when you are turned into a USGI M1 Pack Mule, you will want to shave weight. A lighter barrel means more ammo or some other essential item. |
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