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Posted: 7/13/2005 12:12:14 PM EDT
[#1]
Actually, in the Crane Test To Destruction, the M4 profile survived longer than the heavier M16A2 profile barrel did.
I suspect it is because the barrel gets hot enough that the steel begins to lose strength and droop and that the extra weight and longer lever of the A2 profile means the droop happens faster. There is less weight in front of the M4 profile, so the droop takes a bit longer. Don't know how an HBAR would fare but since it also has increased thickness at the chamber end of the barrel to support the extra weight, I don't think it would necessarily do worse. |
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Posted: 7/13/2005 12:19:03 PM EDT
[#2]
Makes the 4140 vs 4150 debates... kinda moot...eh?
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Posted: 7/13/2005 12:19:52 PM EDT
[#3]
Well actually, this is exactly the kind of failure that 4150 is supposed to resist better.
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Posted: 7/13/2005 12:51:42 PM EDT
[#4]
I just looooove educational threads!
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Posted: 7/13/2005 1:01:19 PM EDT
[#5]
Any idea if these barrels were chambered in .223 or 5.56 and what ammunition they were using? Thank you.
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Posted: 7/13/2005 1:08:46 PM EDT
[#7]
How so? They didnt test any 4150 along side it. |
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Posted: 7/13/2005 4:11:12 PM EDT
[#8]
I think the point being made between 4140 and 4150 is exactly how much useful benefit is there to 4150 over 4140. At ~20,000 rounds at a very stressful shooting regiment, 4150 might give 25 or 30,000 under same conditions. The question is how often will those extra 5 to 10,000 rounds be useful barring military applications?
It's like measuring the advantage of 130 terabytes of data storage and 200 terabytes. The extra 70tb is good but will it ever be used by you and Joe civilian? 130tb is a LOT of porn. A WHOLE LOT!   
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Posted: 7/13/2005 4:40:52 PM EDT
[#9]
hmmm...I could use that last pictured one on some cold, lonely nights...
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Posted: 7/13/2005 4:53:53 PM EDT
[#10]
The M4 SOCOM barrels were HBARs with the M4 cut after the sight base. So basically M4 profile but heavy under the handguards IIRC. Similar to Rock River's R4 barrel.
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Posted: 7/13/2005 5:18:56 PM EDT
[#11]
I think the important thing here to note is that this test required upwards of 18,000 rounds multiplied times several barrels....
The thought of burning ammo at such an incredible rate is what makes the baby jesus cry. Rather than destroying 4 barrels couldn't you have just done 2-3 barrels and sent me the surplus ammo that would have gone into destroying the spared barrel? |
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Posted: 7/13/2005 5:34:26 PM EDT
[#12]
This is the primary reason that the SOCOM (I hate the overused term) barrel was born. The barrel gets so hot where it reached its transformation temp (over 1200F IIRC) and lose its structural integrity. The exact cause was not determined 100% but they designed in the heavier barrels for durability.
ETA, this info is from Black Rifle II, very good readin BTW. Oh, and thanks for posting the pics, it's really an eye opener and shows that I could probably never wear out my barrel (well, not for a few years at least  )
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Posted: 7/13/2005 5:39:15 PM EDT
[#13]
Thanks for posting this.
I like seeing actual information in the forum occasionally.  WIZZO |
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Posted: 7/13/2005 6:11:20 PM EDT
[#14]
I try to keep it real. Remember the test was not really about barrels but other components. The barrel data was a side effect, useful/informative, but a side effect. The testing would most likely been performed differently if it was strictly about barrel performance and longevity. I find it comforting to know just how strong our basic barrels are and how much they can be abused before catastrophic failure. BTW there were 18 uppers in rotation in this test. This serious type testing. For instance LMT has informed me they will not be making a 6.8 MRP upper until they have 150,000 to 200,000 rounds of 6.8 for test purposes. This is the kind of testing the serious companies do prior to releasing products to .mil or us. This type of approach should be commended , understood and appreciated. Denny |
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Posted: 7/13/2005 6:19:36 PM EDT
[#15]
tag
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Posted: 7/13/2005 6:20:09 PM EDT
[#16]
The barrels were marked 5.56 so I assume the chambers were 5.56. Chamber measurements after the fact would be vague at best. I believe the ammo mentioned to me was PMC. Denny |
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Posted: 7/13/2005 6:24:37 PM EDT
[#17]
repub18 your'e right ...I would probably been better to have made a statement of inference..
I was thinking more along my own civilian uses and wants of 4150 barrels vs 4140 and this 4140 barrel wasn't even chrome lined..too boot... Point being ..for my own personal non full auto plinking and back yard varmint shooting... and out to the short range with the kiddies...these barrels are a lot more hardy than I had believed.. But you are right...would be interesting to see how an equal barrel of 4150 and chrome lined would have fared alongside. |
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Posted: 7/13/2005 8:14:06 PM EDT
[#18]
damn........
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Posted: 7/13/2005 8:22:18 PM EDT
[#19]
wazzat, like $4000 per barrel in ammo..roughly?
damn. |
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Posted: 7/13/2005 9:34:05 PM EDT
[#20]
I was at Denny's store in KC MO this past weekend while in town to see Tom Petty/Black Crowes and I must say they have a pretty sweet store. Tons of really cool stuff you usually only see online that you can pick up and see if you like. They don't act annoyed or treat you like a pain in the ass when you ask to look at stuff. I would suggest that anyone in the area or online certainly look them up as they seem to be an excellent outfit to work with. The only thing I didn't like was the drug dealers/gang bangers that came in to buy several hundred rounds of SS109 and a Beta for a stolen weapon....Im not faulting Dennys for this, just sharing a frustrating experience. It was wild to see that stuff being paid for with a giant wad of 100's especially by guys who didn't know what caliber an AR was. It was especially wild to learn that they are having a record number of murders there.
 Oh well...anyways, check out Dennys they have a great little store.
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Posted: 7/13/2005 10:14:57 PM EDT
[#21]
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Posted: 7/13/2005 11:53:34 PM EDT
[#22]
coldblue was part of the M16A2 project - If I recal him correctly the 1:7 guns failed the gageing sooner - but it was found out the barrles where just fouled... |
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Posted: 7/14/2005 12:24:00 AM EDT
[#23]
You can tell people are gang bangers and drug dealers who'd commiited murder and had a stolen weapon just by looking at them? |
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Posted: 7/14/2005 12:47:06 AM EDT
[#24]
You should check out what the guys up at Boeing do! |
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Posted: 7/14/2005 5:00:24 AM EDT
[#25]
IM sent. The pics Variablebinary posted are of the SOCOM. The difference, as others have mentioned, is the thickness under the handguards, where the failures occured. Makes the M4 a bit more full auto friendly. |
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Posted: 7/14/2005 7:09:19 AM EDT
[#26]
That is good news, would hate to think you could only get like 6,000 rounds out of a 1/7 before accuracy went really bad. It is odd that during an accuracy test that the testers would leave enough fouling in the bore to effect accuracy to the degree that it did. |
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Posted: 7/14/2005 7:27:16 AM EDT
[#27]
I wonder if 416 or 410 SS would have lasted even longer... |
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Posted: 7/14/2005 7:49:40 AM EDT
[#28]
And would this be the start of the "1/7 barrels wear out faster" internet myth? |
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Posted: 7/14/2005 8:10:46 AM EDT
[#29]
How would the twist rate affect the barrel life?
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Posted: 7/14/2005 9:08:53 AM EDT
[#30]
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Posted: 7/14/2005 9:21:51 AM EDT
[#31]
If my understanding of metalurgy is correct, it would have failed even sooner. |
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Posted: 7/14/2005 10:40:42 AM EDT
[#32]
Denny wrote: "This is serious-type testing. For instance, LMT has informed me they will not be making a 6.8 MRP upper until they have 150,000 to 200,000 rounds of 6.8 for test purposes."
If they're interested in an intermediate cartridge and need 200,000 rounds, have them pick up the phone and give Bill Alexander a call! Or maybe they want to wait until Wolf ships their 6.5 Grendel ammo? Then they can shoot 400,000 rounds for the same price! John |
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Posted: 7/14/2005 11:45:57 AM EDT
[#33]
John - it sounded like AA was not interested in having a MRP built in 6.5...
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Posted: 7/14/2005 12:06:25 PM EDT
[#34]
Kevin, check IM, so as not to lead this thread astray from its original purpose.
Back to the topic: So 416 stainless is weaker than 4140? Noveske told me the "special" guys he sells to generally prefer stainless. Perhaps the difference is not a concern, or stainless has other advantages that outweigh the "barrel-burst at 18,000 rounds" issue? John |
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Posted: 7/14/2005 12:17:00 PM EDT
[#35]
Thank you for puting to rest all rumored failures for awhile. In the marines we were doing a combined arms exercise and were told we would have to hump out all our ammo if it was not expended. I personaly put 500+ rounds thru mine on burst in about 1/2 hour. It got scary hott, but it remained accurate enough to allow a 231 expert score the next month. Now adays, I do not wory about wearing out my target guns. They will be ready and steady.
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Posted: 7/14/2005 1:42:01 PM EDT
[#36]
Kinda gives a new respect for DPMS, and other makers that use Wilson barrels.
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Posted: 7/14/2005 2:19:46 PM EDT
[#37]
Thanks for posting this. Denny!
Huntr |
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Posted: 7/14/2005 2:35:37 PM EDT
[#38]
Ok,
All this testing and no video of it??? That makes me sad  Denny, Did you ask if video footage was taken? |
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Posted: 7/14/2005 3:12:37 PM EDT
[#39]
There is a big difference between putting 500+ round thru a barrel in 30 minutes and doing the same thing in 3 1/2 minutes (a popped barrel being one of them). |
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Posted: 7/14/2005 3:23:45 PM EDT
[#40]
Interesting how much hotter the barrels got before the gas port. From the pictures it looks like the end of the barrels were much cooler when some of the gas was blead off. Don't seen any barrel falures after any of the gas ports.
Not that this means anything, just interesting. MadDog 
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Posted: 7/14/2005 3:25:58 PM EDT
[#41]
The closer to the chamber, the hotter.
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Posted: 7/14/2005 9:47:08 PM EDT
[#42]
amen, and thank you denny for this thread... very informative! |
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Posted: 7/15/2005 11:49:38 AM EDT
[#43]
I can't tell if people are drug dealers/gang bangers by looking at them....I wish.
I can tell when things aren't right. I cannot imagine a situation where you would buy an AR 15 from anyone under any legit circumstance and not know what caliber it is. The two gentlemen were in the store being extremely shady*it was busy, so it went un noticed* they were trying to find a weapon that most matched theirs looking at some of the LMTs on the counter trying to discern the caliber. One mentioned this looked like thiers without the "shit" on it. They still were confused so they asked for help and an employee went out to their car to positively identify thier weapon as an AR 15, which was in the back seat. *this happend like a minute after a cop left* The two gentlemen *wearing diamonds/platinum, but driving a Nissan box* proceeded to inquire about drum magazines and they were shown a Cmag, which they bought immediatly along with 100 rounds of SS109, and a bunch of 9 and 10mm ammo which was paid for with cash, out of a giagantic wad of 100's. There was likely 8000+ in this wad... This just seemed really odd to me. Maybe that happens all the time there, but it seemd really odd to me. It was extremely suspicious. Its not like its the stores fault, they can't help who shops there. I just prayed that it would be a prop in a rap video, not a prop in worlds wildest police videos. |
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Posted: 7/16/2005 2:26:25 PM EDT
[#44]
Which is why the Government profile barrel is an Abominationn and Morally Offensive to the Righteous. I won't have a Government profile on my ARs. |
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Posted: 7/16/2005 3:27:05 PM EDT
[#45]
When I was younger and without the benefit of a decent education, I had the misfortune of working in retail. You'd be surprised how often want to buy something, but not know what they are shopping for, or have vague knowledge on products |
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Posted: 7/16/2005 4:02:58 PM EDT
[#46]
Great post, but what's the deal on the rest of the test? How did every thing else hold up. At what point did the FSB swell enough to allow the posts to pop out? How about those HG's? Wonder how 4150w/vanadium would have done?
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Posted: 7/17/2005 7:13:09 PM EDT
[#47]
Denny, too bad your Operator barrels were not done yet...
It would have been informative to have one go through the same firing routine as these M-4 types... |
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Posted: 7/23/2005 1:49:08 AM EDT
[#48]
freaking wow
I would think that this calmed a lot of fears. |
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Posted: 7/24/2005 6:37:34 AM EDT
[#49]
In the first gulf war we did an unexpected experiment......
Blew up a barrel of an M16A1 with full auto of tracers....... only took three and a half mags on full auto.... |
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Posted: 8/4/2005 7:57:35 AM EDT
[#50]
The PDF of the Crane test says M4A1, which presumably has the "SOCOM" barrel that is heavier under the HGs than the M16A2's govt profile barrel (though I couldn't find anything to confirm or refute that in the file). I believe a regular M4 barrel is the same diameter as the M16A2 at the rupture point and would likely fail in about the same number or rounds. Based on these two tests we can infer that: 1) 5-600 rounds on full-auto with no breaks to cool will blow up even a good chrome-lined 4150 barrel. 2) If you stop every 200 rounds and let it cool down a bit even an un-lined 4140 barrel will last a long time before it becomes dangerous; probably longer than the shooter's ammo supply. What we don't know is how long it takes to ruin the accuracy of the barrel. |
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