AR15.Com Archives
 4150 vs 4140 barrel steel
defenderhome  [Team Member]
1/7/2007 12:53:26 PM EST
May be a repeat but at the risk of getting flamed...

Doesn't the chrome lining negate issues with barrel steel since the bullet only contacts chrome?

And BTW, was does "Full auto rating" mean? I saw this under someone's ad for an expensive barrel. What is the difference?

Thanks for your time.
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Bartholomew_Roberts  [Team Member]
1/7/2007 2:50:31 PM EST

Doesn't the chrome lining negate issues with barrel steel since the bullet only contacts chrome?


It isn't about barrel life so much as resistance to high temperatures. 4150 has a tiny bit more carbon than 4140 which in turn translates to a higher melting point. So a 4140 barrel might burst at 1500F where a 4150 barrel would burst at 1700F.

For comparison, seven mags of full auto as fast as you can change mags will usually put you in the neighborhood of 600F with an M4 barrel.
splitbolt  [Member]
1/7/2007 2:54:01 PM EST
"Full auto rating" is used to describe 4150 steel.
defenderhome  [Team Member]
1/7/2007 6:24:05 PM EST
Thanks for the info.

I thought the "Full auto" rating was a bit overrated.

I am still not clear on why in this world of the informed buyer that major companies still use 4140. I know it is less wear and tear on the cutting equipment but it seems to be becoming more about "mil spec" these days. Why not have the "percieved" best?
Phoebus  [Team Member]
1/8/2007 10:16:52 AM EST

Originally Posted By defenderhome:
Thanks for the info.

I thought the "Full auto" rating was a bit overrated.

I am still not clear on why in this world of the informed buyer that major companies still use 4140. I know it is less wear and tear on the cutting equipment but it seems to be becoming more about "mil spec" these days. Why not have the "percieved" best?


Because the even more informed buyer knows he doesn't need 4150 and will be happy to pay a bit less for 4140.
BattleRife  [Member]
1/8/2007 6:24:17 PM EST

Originally Posted By defenderhome:
Thanks for the info.
I am still not clear on why in this world of the informed buyer that major companies still use 4140. I know it is less wear and tear on the cutting equipment but it seems to be becoming more about "mil spec" these days. Why not have the "percieved" best?


Don't kid yourself, most of the buyers out there aren't all that well informed. Even those that think they know, usually don't, and barrels are a perfect example. Making barrels from 4150 steel is old technology, think M1 Garand, and is far from the current best choice. Yet the word has got around AR15.com that "mil-spec" barrels are 4150, and now customers are so convinced they know what they are talking about that manufacturers have to hide the fact that they are using good barrel steels, and instead claim to use the inferior 4150 because its the only way they can get customers to buy their barrels. I suspect AR-15 manufacturers chuckle themselves to sleep at nights thinking about their "informed" buyers.
Blacksnake  [Member]
1/9/2007 6:48:16 AM EST

Originally Posted By BattleRife:

Originally Posted By defenderhome:
Thanks for the info.
I am still not clear on why in this world of the informed buyer that major companies still use 4140. I know it is less wear and tear on the cutting equipment but it seems to be becoming more about "mil spec" these days. Why not have the "percieved" best?


Don't kid yourself, most of the buyers out there aren't all that well informed. Even those that think they know, usually don't, and barrels are a perfect example. Making barrels from 4150 steel is old technology, think M1 Garand, and is far from the current best choice. Yet the word has got around AR15.com that "mil-spec" barrels are 4150, and now customers are so convinced they know what they are talking about that manufacturers have to hide the fact that they are using good barrel steels, and instead claim to use the inferior 4150 because its the only way they can get customers to buy their barrels. I suspect AR-15 manufacturers chuckle themselves to sleep at nights thinking about their "informed" buyers.


Exactly what alloy makes 4150 "inferior" as compared to (that is a common barrel steel)??? They are "hiding" the fact they use good barrel steels by claiming to use 4150???

ChromeLined  [Member]
1/9/2007 6:55:12 AM EST
4150 inferior?ahh...ok next well hear the 8620 steel M14 receivers were made from is garbage too.
markm  [Team Member]
1/9/2007 6:58:56 AM EST

Originally Posted By ChromeLined:
4150 inferior?ahh...ok next well hear the 8620 steel M14 receivers were made from is garbage too.


It's a Canadian reply, dude. Draw your own conclusions.
45FMJoe  [Member]
1/9/2007 7:08:00 AM EST

Originally Posted By markm:

Originally Posted By ChromeLined:
4150 inferior?ahh...ok next well hear the 8620 steel M14 receivers were made from is garbage too.


It's a Canadian reply, dude. Draw your own conclusions.


Dude, I just burst out laughing in the middle of a cafeteria at USF. People are looking at me funny. I almost fell out of my chair, seriously. That was flippin' hilarious.
BattleRife  [Member]
1/9/2007 8:55:15 AM EST

Originally Posted By Blacksnake:

Exactly what alloy makes 4150 "inferior" as compared to (that is a common barrel steel)??? They are "hiding" the fact they use good barrel steels by claiming to use 4150???


Strong language to get your attention. 4150 is not a lousy choice, but it is an inferior choice. Like I said, 4150 was cutting edge when the M1 Garand was adopted in 1937, but it is not now, and hasn't been for 50 years. Despite the nonsense you see repeated over and over and over again on this website, there is strong evidence that 4150 steel is not mil-spec for the AR-15, and I doubt that Colt or FN ever put a single 4150 barrel on a production AR-15.

Bravo Company, a well-known dealer here, a few months ago had a Colt M4 barrel tested for chemical composition. It was NOT a match for anybodies definition of 4150 steel. A while before that, he had FN M16A2 barrel tested, and it was also not 4150. Yet people don't see the light, and go on yakking about 4150.

Which is why you get the current situation. Bushmaster, on their website, states they make their barrels from mil-spec Cr-Mo-V steel. Then they go on to state that their barrels are 4150. Well, news flash, Cr-Mo-V steel and 4150 steel are exclusive compositions, a material must be one or the other: it cannot be both. There is no allowance in the 41xx steel series for intentional vanadium additions. I firmly believe that Bushmaster is making their barrels from Cr-Mo-V ordnance steel, per MIL-B-11595, but that the racket from the peanut gallery over 4150 is so overwhelming that the marketing folks have found a way to slip those magic numbers into a few points in the website to shut people up. You see the same thing with Denny's "Operator" barrels. I honestly wonder if a single manufacturer out there is using 4150 steel in AR-15 barrels. Certainly the top ones are not.

4150 steel in AR-15 barrels is the greatest firearms-internet myth extant. We sensible people here north of the border would like to see it slain.
LoneWolfUSMC  [Member]
1/9/2007 9:03:09 AM EST
<--- Blissful in my ignorance.

For my duty rifles I buy "Military Contract" barrels. This is one of the reasons I have a 14.5" on my M4gery. Why? Because I know from experience they are accurate enough for my purposes, will withstand the elements, hard use and cleaning, AND a higher rate of fire than my trigger finger is capable of.

I will leave the "type of steel" arguments to the engineers. I am an "end-user". As long as it accomplishes the mission, then it's good enough for me.
TheMocoMan  [Team Member]
1/9/2007 10:29:35 AM EST
WOW.

I guess even folks like Noveke don't know what they're talking about when the make references to this "milspec 4150 steel stuff"

Noveske 17-4 Extreme Duty Barrels linky
"After months of research, development, and testing, we are happy to announce our new Extreme Duty Barrels. The barrel is made of 17-4 H1075 Stainless with a Rockwell hardness of 36-38. This is up to 30% harder than mil-spec 4150 barrel steel. The barrel is harder, tougher, and more resistant to erosion than other barrels. Benefits: Sub MOA accuracy Minimal to NO Fouling Extended Barrel Life Higher operating temperatures."

of course fucking Noveske can't spell "temperatures" correctly. BUT WHO CARES!
BattleRife  [Member]
1/9/2007 2:10:11 PM EST

Originally Posted By TheMocoMan:
WOW.

I guess even folks like Noveke don't know what they're talking about when the make references to this "milspec 4150 steel stuff"


There is every possibility that Noveske does know what they are talking about, as there is such a material as mil-spec 4150 barrel steel. It was used on the M1 Garand. It was used on many, if not all, M14s. It is not, however, used on Colt or FN AR-15s, and nowhere in the statement you quoted does Noveske claim it is.
JER  [Member]
1/9/2007 2:13:45 PM EST

Originally Posted By BattleRife:
there is such a material as mil-spec 4150 barrel steel. It was used on the M1 Garand. It was used on many, if not all, M14s. It is not, however, used on Colt or FN AR-15s, and nowhere in the statement you quoted does Noveske claim it is.

Well, number one, you are wrong about Colt ARs. I'm not even going to get into a pissing match about it. People who post such crap aren't worth it.

Number two, FN does not make AR15s.
JER  [Member]
1/9/2007 2:15:25 PM EST
To the OP, unless you are going to shoot full auto often, or get into firefights where you are going to burn mag after mag after mag, 4140 Chrome Molybdenum steel has all the metallurgical and thermal properties to make your rifle a safe and durable one.
birddogz  [Member]
1/9/2007 2:46:13 PM EST
Industry » Bravo Company USA, Inc » Barrel Steel: 4150, 4140, Chrome Moly, Chrome Moly Vanadium

Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."
ChromeLined  [Member]
1/9/2007 2:54:25 PM EST
Maybe hes just mad that Colt bought out Dimaeco.If Im not mistaken isnt 4150 steel specified in the TDP.
Blacksnake  [Member]
1/9/2007 3:38:06 PM EST

Originally Posted By BattleRife:

Originally Posted By Blacksnake:

Exactly what alloy makes 4150 "inferior" as compared to (that is a common barrel steel)??? They are "hiding" the fact they use good barrel steels by claiming to use 4150???


Strong language to get your attention. 4150 is not a lousy choice, but it is an inferior choice. Like I said, 4150 was cutting edge when the M1 Garand was adopted in 1937, but it is not now, and hasn't been for 50 years. Despite the nonsense you see repeated over and over and over again on this website, there is strong evidence that 4150 steel is not mil-spec for the AR-15, and I doubt that Colt or FN ever put a single 4150 barrel on a production AR-15.

Bravo Company, a well-known dealer here, a few months ago had a Colt M4 barrel tested for chemical composition. It was NOT a match for anybodies definition of 4150 steel. A while before that, he had FN M16A2 barrel tested, and it was also not 4150. Yet people don't see the light, and go on yakking about 4150.

Which is why you get the current situation. Bushmaster, on their website, states they make their barrels from mil-spec Cr-Mo-V steel. Then they go on to state that their barrels are 4150. Well, news flash, Cr-Mo-V steel and 4150 steel are exclusive compositions, a material must be one or the other: it cannot be both. There is no allowance in the 41xx steel series for intentional vanadium additions. I firmly believe that Bushmaster is making their barrels from Cr-Mo-V ordnance steel, per MIL-B-11595, but that the racket from the peanut gallery over 4150 is so overwhelming that the marketing folks have found a way to slip those magic numbers into a few points in the website to shut people up. You see the same thing with Denny's "Operator" barrels. I honestly wonder if a single manufacturer out there is using 4150 steel in AR-15 barrels. Certainly the top ones are not.

4150 steel in AR-15 barrels is the greatest firearms-internet myth extant. We sensible people here north of the border would like to see it slain.


For all practical purposes, CMV barrels ARE 4150 with vanadium added for extra wear resistance. Rather than Bushmaster and others saying "Our barrels are made from MIL-B-11595," it makes more sense to me for them to say 4150 as well because that readily differentiates it from 4140. And not everyone knows WTF MIL-XXXXX is, but more folks are aware of the differences between 4140 and 4150, or can easily look the alloys up on matweb to see the differences.

You're reading way too much into this - it's not a marketing gimmick, it's just a simpler way to differentiate steels with properties closer to 4150 from 4140.

MIL-B-11595E is for 4150, 4150 resulferized and CMV. Not to damn much difference between the three either.

The reality is that no one's barrel steels are on the "cutting edge" of metallurgy, because few can afford a $10,000 barrel. They are good steels that are adequate for the task at hand within a reasonable price range.

I should add also, 4140 is fine for most people's end uses other than military. The chrome lined barrels are nice because they are easy to clean and the chromed chamber does help with extraction (not to mention the increased lifespan of the barrel).
BattleRife  [Member]
1/9/2007 4:06:30 PM EST

Originally Posted By Blacksnake:
For all practical purposes, CMV barrels ARE 4150 with vanadium added for extra wear resistance. Rather than Bushmaster and others saying "Our barrels are made from MIL-B-11595," it makes more sense to me for them to say 4150 as well because that readily differentiates it from 4140. And not everyone knows WTF MIL-XXXXX is, but more folks are aware of the differences between 4140 and 4150, or can easily look the alloys up on matweb to see the differences.

The reality is that no one's barrel steels are on the "cutting edge" of metallurgy, because few can afford a $10,000 barrel. They are good steels that are adequate for the task at hand within a reasonable price range.


I must disagree with your first point. The Cr-Mo-V steel under discussion differs significantly from 4150 in several respects, not just the presence of vanadium. The 4150 alloy follows AISI conventions for compositional ranges, and has manganese, sulphur, phosphorus, silicon, chromium and molybdenum levels that are essentially the same as all other 41xx alloys. The Cr-Mo-V steel listed in MIL-B-11595 has .45%C (nom.), a noticeably wider tolerance on carbon content, a lower manganese content and a higher molybdenum content than anything seen in the 41xx series. Cr-Mo-V cannot be called the same as 4150 any more than an orange can be called the same as a tangerine.

As an aside, the vanadium is not there for wear resistance, it is there to increase hot hardness and provide grain refinement which will improve stress-rupture characteristics. The higher molybdenum levels will also add to hot hardness.

I will agree that no rifle barrel features cutting edge metallurgy. This is largely because there really is very little left in metallurgical sciences that can be considered "cutting edge", it is a very mature business. Which is all the more reason why there is no excuse to be spreading misleading information when the proper materials and specifications were made public knowledge 50 years ago.
BattleRife  [Member]
1/9/2007 4:14:59 PM EST

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.
BravoCompanyUSA  [Industry Partner]
1/9/2007 4:30:13 PM EST

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.


That is very true. 4150 is not CMV, they are very different steels.

My point was that the description of "4150" is used (albiet misused for accuracy) to describe a both 4150 and CMV. Often the 'grade' description will read 4150M or 4150MOD for CMV.
We are in agreement, that type of description is not accurate. Because 4150 and CMV are not the same steel. I was just trying to relay how some of the term are used by the barrel/steel mills. I do not specifically agree with the accuracy of some of the terms used. I am just reporting what I see on the paperwork.


Just for general clairification -- just because a steel is 4150 or CMV does not mean it is Milspec. A milpsec steel is a ORD4150, 4150 Resulferinzed, or CMV that meets all the various specifications in MIL-B-11595E.

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.
P229SAS  [Member]
1/9/2007 6:51:23 PM EST
So what exactly does Bushmaster use?
Rob96  [Member]
1/10/2007 1:02:58 AM EST

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


And there you have it. I can't think of any better opinion.
Brazos_Jack  [Member]
1/10/2007 2:46:12 AM EST

Originally Posted By BravoCompanyUSA:

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.


That is very true. 4150 is not CMV, they are very different steels.

My point was that the description of "4150" is used (albiet misused for accuracy) to describe a both 4150 and CMV. Often the 'grade' description will read 4150M or 4150MOD for CMV.
We are in agreement, that type of description is not accurate. Because 4150 and CMV are not the same steel. I was just trying to relay how some of the term are used by the barrel/steel mills. I do not specifically agree with the accuracy of some of the terms used. I am just reporting what I see on the paperwork.


Just for general clairification -- just because a steel is 4150 or CMV does not mean it is Milspec. A milpsec steel is a ORD4150, 4150 Resulferinzed, or CMV that meets all the various specifications in MIL-B-11595E.

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


I really wouldn't get my panties in a wad either way. Often large manufacturers that buy entire mill runs of a certain alloy will have special steels made. For convenience, their metalurgists will start working with the steel company using a known AISI composition as a starting point. They will then change the composition 6 ways to Sunday and call it AISIXXXX "Modified". It may bear little resemblance to the original AISIXXXX, but sooner or later everyone associated with the company will refer to it as if it were a standard you could get anywhere. The former Byron Jackson Pump Company, now BJ Services, has a lot of pump parts made from what they call "4130 Modified". It's compositon has been so extensively modified that it's heat treat response, weldability and carbon equivelency are much closer to 4140. And if you went to any steel company except their original supplier and asked for "4130 Modified" no telling what you'd get. So I really can't get too bent about what is really a common missuse of AISI terminology. So strictly speaking, no, it may not be 4150, but it still may have "4150" or "4150 Modified" plastered all over the purchasing specs.
Blacksnake  [Member]
1/10/2007 6:33:27 AM EST

Originally Posted By BravoCompanyUSA:

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.


That is very true. 4150 is not CMV, they are very different steels.

My point was that the description of "4150" is used (albiet misused for accuracy) to describe a both 4150 and CMV. Often the 'grade' description will read 4150M or 4150MOD for CMV.
We are in agreement, that type of description is not accurate. Because 4150 and CMV are not the same steel. I was just trying to relay how some of the term are used by the barrel/steel mills. I do not specifically agree with the accuracy of some of the terms used. I am just reporting what I see on the paperwork.


Just for general clairification -- just because a steel is 4150 or CMV does not mean it is Milspec. A milpsec steel is a ORD4150, 4150 Resulferinzed, or CMV that meets all the various specifications in MIL-B-11595E.

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


Please clarify what you mean by very different in terms of properties (tensile strength, hardness, etc.), mainly for my curiosity because I'm not around the book where I could readily look this up for CMV specified by MIL-B-11595E - It is likely the end user in any extreme will find very little difference in the field between 4150 and CMV, but I could be wrong.
Blacksnake  [Member]
1/10/2007 6:46:43 AM EST

Originally Posted By BattleRife:

Originally Posted By Blacksnake:
For all practical purposes, CMV barrels ARE 4150 with vanadium added for extra wear resistance. Rather than Bushmaster and others saying "Our barrels are made from MIL-B-11595," it makes more sense to me for them to say 4150 as well because that readily differentiates it from 4140. And not everyone knows WTF MIL-XXXXX is, but more folks are aware of the differences between 4140 and 4150, or can easily look the alloys up on matweb to see the differences.

The reality is that no one's barrel steels are on the "cutting edge" of metallurgy, because few can afford a $10,000 barrel. They are good steels that are adequate for the task at hand within a reasonable price range.


I must disagree with your first point. The Cr-Mo-V steel under discussion differs significantly from 4150 in several respects, not just the presence of vanadium. The 4150 alloy follows AISI conventions for compositional ranges, and has manganese, sulphur, phosphorus, silicon, chromium and molybdenum levels that are essentially the same as all other 41xx alloys. The Cr-Mo-V steel listed in MIL-B-11595 has .45%C (nom.), a noticeably wider tolerance on carbon content, a lower manganese content and a higher molybdenum content than anything seen in the 41xx series. Cr-Mo-V cannot be called the same as 4150 any more than an orange can be called the same as a tangerine.

As an aside, the vanadium is not there for wear resistance, it is there to increase hot hardness and provide grain refinement which will improve stress-rupture characteristics. The higher molybdenum levels will also add to hot hardness.

I will agree that no rifle barrel features cutting edge metallurgy. This is largely because there really is very little left in metallurgical sciences that can be considered "cutting edge", it is a very mature business. Which is all the more reason why there is no excuse to be spreading misleading information when the proper materials and specifications were made public knowledge 50 years ago.


It's obvious from reading MIL-B-11595E that the military would more or less consider all three alloys interchangeable, otherwise they would have written the spec for one specific alloy (i.e. - CMV), would they not? Why include 4150, 4150 resulferized and CMV all three in the spec for small arms barrel blanks when only CMV will do or if CMV is "very" different from 4150 from a durability/strength standpoint?

So I stand by what I said, "for all practical purposes" (i.e. - ability to bust caps quickly and in a durable fashion) 4150 and CMV are the same.
BravoCompanyUSA  [Industry Partner]
1/10/2007 6:51:55 AM EST

Originally Posted By Brazos_Jack:

I really wouldn't get my panties in a wad either way. Often large manufacturers that buy entire mill runs of a certain alloy will have special steels made. For convenience, their metalurgists will start working with the steel company using a known AISI composition as a starting point. They will then change the composition 6 ways to Sunday and call it AISIXXXX "Modified". It may bear little resemblance to the original AISIXXXX, but sooner or later everyone associated with the company will refer to it as if it were a standard you could get anywhere. The former Byron Jackson Pump Company, now BJ Services, has a lot of pump parts made from what they call "4130 Modified". It's compositon has been so extensively modified that it's heat treat response, weldability and carbon equivelency are much closer to 4140. And if you went to any steel company except their original supplier and asked for "4130 Modified" no telling what you'd get. So I really can't get too bent about what is really a common missuse of AISI terminology. So strictly speaking, no, it may not be 4150, but it still may have "4150" or "4150 Modified" plastered all over the purchasing specs.


Thanks for the info. It is always interesting to see how terms and descriptions evolve within an industry.
BravoCompanyUSA  [Industry Partner]
1/10/2007 6:59:52 AM EST

Originally Posted By Blacksnake:

Originally Posted By BravoCompanyUSA:

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.


That is very true. 4150 is not CMV, they are very different steels.

My point was that the description of "4150" is used (albiet misused for accuracy) to describe a both 4150 and CMV. Often the 'grade' description will read 4150M or 4150MOD for CMV.
We are in agreement, that type of description is not accurate. Because 4150 and CMV are not the same steel. I was just trying to relay how some of the term are used by the barrel/steel mills. I do not specifically agree with the accuracy of some of the terms used. I am just reporting what I see on the paperwork.


Just for general clairification -- just because a steel is 4150 or CMV does not mean it is Milspec. A milpsec steel is a ORD4150, 4150 Resulferinzed, or CMV that meets all the various specifications in MIL-B-11595E.

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


Please clarify what you mean by very different in terms of properties (tensile strength, hardness, etc.), mainly for my curiosity because I'm not around the book where I could readily look this up for CMV specified by MIL-B-11595E - It is likely the end user in any extreme will find very little difference in the field between 4150 and CMV, but I could be wrong.


If you are referencing "very different steels" (your bold and enlarged font ephasis), I am speaking in the context of chemical composition. As it relates to properties, I have no idea. That is something that the metallurgists can debate. In my orginal chemical analysis post (copy of that post here) I stated that Uncle Sam (Mil-B-11595E) did not have a bias of one type of steel over another (of the 3 types listed). So Uncle Sam considers them interchangable.
AzzKicker  [Member]
1/10/2007 7:07:22 AM EST

Originally Posted By BravoCompanyUSA:

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.



By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


But Oh No's!!!! I GOTTA Have MILSPEC bbl's!!! Because if its not MILSPE, its not 1337'zors :)

Blacksnake  [Member]
1/10/2007 10:33:54 AM EST

Originally Posted By BravoCompanyUSA:

Originally Posted By Blacksnake:

Originally Posted By BravoCompanyUSA:

Originally Posted By BattleRife:

Originally Posted By birddogz:
Bravo Company concluded that the colt barrel met the specs.

"So in describing a USGI (Colt) M16/M4 barrel it is generally done this way on spec sheets:
Barrel Steel
Grade: 4150
Specification: Mil-B-11595E
And then as part of the Certification documents (certs) would be the chemical analysis to list CMV."


While I referenced Bravo Company for the measured data, I do not agree at all with his conclusions. He admits, in his post, that he was surprised that the Colt barrel did not meet the specs for 4150, but then somehow surmised than any metal covered by MIL-B-11595 could be referred to as 4150, with a statement at the end to clarify the alloy as Cr-Mo-V. This does not make sense.

4150 is not Cr-Mo-V. Cr-Mo-V is not 4150. Just because they both appear in the same milspec does not make the terms interchangeable.


That is very true. 4150 is not CMV, they are very different steels.

My point was that the description of "4150" is used (albiet misused for accuracy) to describe a both 4150 and CMV. Often the 'grade' description will read 4150M or 4150MOD for CMV.
We are in agreement, that type of description is not accurate. Because 4150 and CMV are not the same steel. I was just trying to relay how some of the term are used by the barrel/steel mills. I do not specifically agree with the accuracy of some of the terms used. I am just reporting what I see on the paperwork.


Just for general clairification -- just because a steel is 4150 or CMV does not mean it is Milspec. A milpsec steel is a ORD4150, 4150 Resulferinzed, or CMV that meets all the various specifications in MIL-B-11595E.

By the way, plain old 4140 is probably more barrel steel than 99% of us reading this post will ever need.


Please clarify what you mean by very different in terms of properties (tensile strength, hardness, etc.), mainly for my curiosity because I'm not around the book where I could readily look this up for CMV specified by MIL-B-11595E - It is likely the end user in any extreme will find very little difference in the field between 4150 and CMV, but I could be wrong.


If you are referencing "very different steels" (your bold and enlarged font ephasis), I am speaking in the context of chemical composition. As it relates to properties, I have no idea. That is something that the metallurgists can debate. In my orginal chemical analysis post (copy of that post here) I stated that Uncle Sam (Mil-B-11595E) did not have a bias of one type of steel over another (of the 3 types listed). So Uncle Sam considers them interchangable.


Thanks! I just wanted to clarify whether that was in terms of composition, or real world application/mechanical properties.
BattleRife  [Member]
1/11/2007 4:58:21 PM EST

Originally Posted By Blacksnake:
It's obvious from reading MIL-B-11595E that the military would more or less consider all three alloys interchangeable, otherwise they would have written the spec for one specific alloy (i.e. - CMV), would they not? Why include 4150, 4150 resulferized and CMV all three in the spec for small arms barrel blanks when only CMV will do or if CMV is "very" different from 4150 from a durability/strength standpoint?

So I stand by what I said, "for all practical purposes" (i.e. - ability to bust caps quickly and in a durable fashion) 4150 and CMV are the same.


I don't think that including 3 different alloys in one spec at all implies that they are interchangeable, it simply means that all 3 are in active use in one application or another. Cr-Mo-V seems to have developed especially to deal with the problems of barrels bursting during sustained firing in lightweight, air-cooled guns. This would not be a problem with a M24, so 4150 might be a better choice for that application. As long as the military has to maintain a spec for multiple materials, they might as well combine as many as possible into one document to reduce duplication. This is absolutely not the same thing as recommending them into the same applications.

Anyway, I agree with everyone that for the home user, the alloy is all but irrelevant. 4140 makes a better barrel than most of us could ever need. But since these questions come up so often, I wanted people to understand that terms are being badly misused, and that the common knowledge (i.e. mil-spec AR-15 barrels are made from 4150 steel) is flat out wrong.
AzzKicker  [Member]
1/11/2007 5:16:08 PM EST

Originally Posted By BattleRife:

Originally Posted By Blacksnake:
It's obvious from reading MIL-B-11595E that the military would more or less consider all three alloys interchangeable, otherwise they would have written the spec for one specific alloy (i.e. - CMV), would they not? Why include 4150, 4150 resulferized and CMV all three in the spec for small arms barrel blanks when only CMV will do or if CMV is "very" different from 4150 from a durability/strength standpoint?

So I stand by what I said, "for all practical purposes" (i.e. - ability to bust caps quickly and in a durable fashion) 4150 and CMV are the same.


Anyway, I agree with everyone that for the home user, the alloy is all but irrelevant. 4140 makes a better barrel than most of us could ever need.


Shit, even LEO and some Military units wouldnt even know the difference. Unless your Full Auto for hours a day I doubt it makes much difference to anyone.
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