View Full Version : Durability: Cold Hammer Forged vs. Button, Polygonal vs. Rifling
I'm curious how MUCH of a difference the following make as far as durability.
I know hammer forging beats out button, but by how much?
I know polygonal beats out rifling, but by how much?
Got any stats on any of these to put them in perspective?
Cold Hammer Forged vs. Button
Polygonal vs. Rifling
Stainless vs. nitrided 4150 cmv
EDIT: I know there are a ton of old threads on this but I can't find any quantitative data. e.g. 20,000 rounds to key-holing for rifling vs 30,000 w/ polygonal.
TacticalMark
03-07-14, 23:41
Do a quick search, https://www.m4carbine.net/showthread.php?52759-Hammer-forged-vs-quot-std-quot-barrels-and-accuracy
There are a few threads on this.
It makes NO difference because the chrome lining doesn't really care what steel is underneath it.
If you're after accuracy, it makes NO difference because you're after accuracy.
Nobody knows and nobody can tell the difference. Manufacturers price one or the other higher and perceived value will dictate which one an individual will buy.
My CHF barrels hold less copper and clean up faster than any other barrels I have or have shot.
It makes NO difference because the chrome lining doesn't really care what steel is underneath it.
If you're after accuracy, it makes NO difference because you're after accuracy.
Nobody knows and nobody can tell the difference. Manufacturers price one or the other higher and perceived value will dictate which one an individual will buy.
Cold hammer forging increases barrel density, and increased barrel density does prolong the life of the chrome lining. Think of a house built on a stronger foundation. The chrome adheres to a more dense surface and is less likely to detach. Other benefits to hammer forging is that it works out imperfections in the barrel blank which improve accuracy, overall durability, and makes the chrome surface more uniform. When the imperfections are worked out of the barrel, the chroming process is more thorough and uniform. It really is the best barrel combination of high volume shooting, durability, and accuracy. Not as accurate as a non chrome-lined match barrel.
I talked to Noveske direct on the phone and they said CHF was the most durable.
Rainier arms says the same on their website:
https://www.rainierarms.com/?page=shop/detail&product_id=4048
I'm just trying to find some quantitative proof of durability differences between different rifling and manufacturing processes.
For instance, Key-holing @ 20,000 rounds would be a great metric.
Do a quick search, https://www.m4carbine.net/showthread.php?52759-Hammer-forged-vs-quot-std-quot-barrels-and-accuracy
There are a few threads on this.
Thank you. However, that doesn't help (much).
1st: This link is dead and I can't find a repost:
http://technology.calumet.purdue.edu/met/higley/Precision%20Shooting%20Magazine%20-%20November-%202005%20%28Vol_%2053%20-%20No_%207%29.htm
2nd: This is the key quote from that thread:
CHF is implied to give advantages in longevity and accuracy but I believe the CHF barrel thing in AR's is mostly hype. sure there may be theoretical differences but no one has been able to quantify those differences that I have seen. ymmv...
This makes me a believer in theory, but I would love quantitative numbers:
Hammer forged barrels have no "chatter" like button rifled ones. My noveske doesn't even hold enough copper to turn bore cleaner blue. That's what made me a believer. Beyond that? I don't know.
3rd: I'm also interested in quantitative differences between rifling types.
rainier also says polygonal has longer life:
https://www.rainierarms.com/?page=shop/detail&product_id=3391
Not this again...
Goodness people use the search button.
Not this again...
Goodness people use the search button.
If it's so easy you find quantitative data. As far as I can tell it doesn't exist.
If it's so easy you find quantitative data. As far as I can tell it doesn't exist.
Because there isn't any. There are no scientific tests to prove exactly how many rounds the barrel will last longer, how the barrel will warp less, and which ones are better.
This has been covered many times. Sure people have run many rounds through each, but there has been no crazy in depth tests on this, and using the search button will show this as it's been disgussed many times. People are just looking for answers to questions that just are not important enough for crazy in depth research to be done.
Outside of that, the accuracy side of things have been covered, but durability/round count is still undecided. In the end who cares, barrels are disposable parts in the grand scheme of things. It will take how many thousands of dollars of ammo to shoot out a barrel... so in that regard, the barrel and even BCG are so small in cost that the question in general IMO is worthless. Shoot the hell out of it, shoot it out, replace it. Nuff said.
Several years old now...
https://www.m4carbine.net/archive/index.php/t-95136.html
http://www.slip2000.com/blog/s-w-a-t-magazine-filthy-14/
Several years old now...
https://www.m4carbine.net/archive/index.php/t-95136.html
http://www.slip2000.com/blog/s-w-a-t-magazine-filthy-14/
That doesn't really show anything though, asides from the filthy 14 that lasted a gazillion rounds. Not a comparison, and doesn't prove anything, other than a BCM standard barrel lasting a long arse time.
That doesn't really show anything though, asides from the filthy 14 that lasted a gazillion rounds. Not a comparison, and doesn't prove anything, other than a BCM standard barrel lasting a long arse time.
Maybe as close as the OP gets.
Maybe as close as the OP gets.
Yup. If I recall, wasn't DD going to do a big ordeal about their HF barrels? Still would have been nice if they purchased a few competitors and did a test along side of them. (this test was mentioned on T.TV).
The problem is that throat erosion is going to be dependent upon both how many rounds are fired and how rapidly those rounds are fired. There is not a definitive number because the manner in which the rounds are fired is a critical component of barrel life. You can make a lower quality barrel last longer and tear up a higher quality barrel faster by simply firing less rounds per minute or more.
Barrels are an expendable component. You will spend many multiples the cost of the barrel by buying ammo before you've "shot out" a barrel from any respected manufacturer. Is there a particular reason you're concerned, or is this simply a question for the sake of learning the science of barrels?
The question could be will you ever see the difference in how and what the barrels are made of. I would look in to the quality. Stainless is softer. A high quality of either will be better than a low quality of either. As mentioned the filthy 14 how much better do you need than that. Maybe if you get into full auto and burn through thousands and thousands of rounds you could see a difference. Quality always wins over razzel dazzel.
sinlessorrow
03-08-14, 19:49
Well the Bushies and the spikes Andrew ran in the lucky gunner labs test were shot out by 6-10k rounds and all were CHF.
I would say 6-10k of extensive fire is what you can expect from a Colt or BCM barrel as well.
wildcard600
03-08-14, 20:24
Well the Bushies and the spikes Andrew ran in the lucky gunner labs test were shot out by 6-10k rounds and all were CHF.
I would say 6-10k of extensive fire is what you can expect from a Colt or BCM barrel as well.
Yes but as was said above, the rate of fire is going to have a massive effect on barrel life. In the lucky gunner test they talk about the rifles getting so hot they couldn't hold them, the average person is not going to burn through 10k rounds that fast.
Heating the barrel steel up to the point of elasticity and then continuing to pour bullets through it is going to tear up any barrel and I don't think the lucky gunner test can really be used as a measure of barrel life, except under rapid fire conditions.
sinlessorrow
03-08-14, 20:26
Yes but as was said above, the rate of fire is going to have a massive effect on barrel life. In the lucky gunner test they talk about the rifles getting so hot they couldn't hold them, the average person is not going to burn through 10k rounds that fast.
Heating the barrel steel up to the point of elasticity and then continuing to pour bullets through it is going to tear up any barrel and I don't think the lucky gunner test can really be used as a measure of barrel life, except under rapid fire conditions.
No doubt, my point was that I would expect the same amount of life from a button rifled Colt barrel as I would a FN CHF barrel if both were fired like Andrew and his people did.
Well the Bushies and the spikes Andrew ran in the lucky gunner labs test were shot out by 6-10k rounds and all were CHF.
I would say 6-10k of extensive fire is what you can expect from a Colt or BCM barrel as well.
Since when has Bushmaster CHF?
Heavy Metal
03-08-14, 21:17
Since when has Bushmaster CHF?
Since Remmingtion started making them apparently.
The Lucky Gunner test is a poor predictor of the long-term durability of any barrel. It was a destructive test by its very nature. The Gator Hide gas checkering of the bore surface and the throat temps they were getting when they were measuring 700+ degrees on the outside of the barrel were likely plenty hot enough to cause greatly accelerated throat erosion, flame cutting and plastic softening of the steel.
It is not remotely representative of a normal or near-normal use pattern and not comparable for those purposes.
Since when has Bushmaster CHF?
Isn't the 16 1/2in ACR barrel CFH?
sinlessorrow
03-08-14, 21:43
Since when has Bushmaster CHF?
For a while now, ever since they got the ACR.
Since Remmingtion started making them apparently.
The Lucky Gunner test is a poor predictor of the long-term durability of any barrel. It was a destructive test by its very nature. The Gator Hide gas checkering of the bore surface and the throat temps they were getting when they were measuring 700+ degrees on the outside of the barrel were likely plenty hot enough to cause greatly accelerated throat erosion, flame cutting and plastic softening of the steel.
It is not remotely representative of a normal or near-normal use pattern and not comparable for those purposes.
Of course, but again I would expect a button rifled barrel to perform on par in the same test.
wildcard600
03-08-14, 21:54
No doubt, my point was that I would expect the same amount of life from a button rifled Colt barrel as I would a FN CHF barrel if both were fired like Andrew and his people did.
Of course, but again I would expect a button rifled barrel to perform on par in the same test.
Ahh.... I see what your saying.
FWIW to the subject of barrel life I probably have close to 10k rounds through my SAR-1 that I bought back in 99' when 7.62 was $60 a case and the bore and chrome is still bright and shiny. I never did a many mag dumps and 99% of those 10K rounds were pretty slow aimed fire.
I guess my point is if its a quality barrel and you don't shoot like John Rambo and John Matrix combined, the barrel will last a long damn time.
thebarracuda
03-08-14, 21:58
I guess my point is if its a quality barrel and you don't shoot like John Rambo and John Matrix combined, the barrel will last a long damn time.
I think this pretty well sums up this entire discussion. If none of us can shoot enough ammo through one to tell, does it really matter? I'm thinking it doesn't.
Don't forget the barrels that were shot out were also barrels shooting bimetal bullets. The M193 barrel had more rounds on it and was still GTG.
Heavy Metal
03-08-14, 23:47
Don't forget the barrels that were shot out were also barrels shooting bimetal bullets. The M193 barrel had more rounds on it and was still GTG.
When steel gets soft, it has more trouble swaging a steel projectile. The projectile deforms the barrel back.
Of course, it you don't cook the shit out of it, it is going to have far less problems.
Some people think the moral is to not use steel. I am cool with that as there is more left for me to use, I just rock on, save money and don't cook my barrels. Please don't buy Russian ammo, EVER!
wildcard600
03-09-14, 00:23
Did you see the m193 barrel ? it was chewed to shit too.... I wouldn't call that kind of damage GTG. Just because it wasn't shooting keyholes yet dosent mean the barrel wasn't already nearly shot.
Please don't buy Russian ammo, EVER!
Kind of rough as far as advice goes.
It would be far better to preach that if you're going to be buying Russian ammo, be prepared for reduced barrel life. Hell, at about $380 for 2K 5.45, I can buy a barrel every two cases and still be behind the dollar curve.
Heavy Metal
03-09-14, 00:53
I am sure used in a semi-normal fashion, you will see a minor reduction in bore life but nothing approaching what the lucky gunner destructive testing revealed.
My belief is if you repeated the test with a more normal firing schedule, you would fine something like a 15 to 20 percent difference in lifespan, not 40 to 60.
Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)
In the IAR test the HK CHF barrel lasted several times longer than it's buttoned competitors.
Several times.
Look up a process called autofrettage, the military has been doing in for decades when it made cannon tube because it yielding stronger, longer lasting barrels.
Autofrettage is similar to what is done when a CHF and it produces a longer lasting tube.
RogerinTPA
03-09-14, 11:20
Kind of rough as far as advice goes.
It would be far better to preach that if you're going to be buying Russian ammo, be prepared for reduced barrel life. Hell, at about $380 for 2K 5.45, I can buy a barrel every two cases and still be behind the dollar curve.
I recently replaced a barrel of one of my 6920s that had 20K+ rounds (used in many carbine courses), with Russian Wolf, Brown Bear, and Golden Tiger (the last two being lacquered coated) shot almost exclusively through it, not because of barrel wear, but for preventive maintenance. I bet I could have gone another 10K rounds fired. I've probably shot 60K+ of Wolf alone to date over 5 carbines. I was still getting 3 MOA shot groups at 100 yards using IMI M193 prior to the swap. You see slewed test like Lucky Gunner's, that shot the weapons doing mag dump after mag dump until the ammo was shot up, with extremely subjective conclusions. They should have used beer cans and dirt clods as targets since it was such a 'bubba' contrived experiment. The fact is, no one shoots a weapon like that, not even those of us that attend several carbine courses a year. I'll say it again as I've said many times, it's a AR, not a belt fed.
The results had more to do with a sustained high rate of fire than ammo selection, although steel cased ammo does have a peripheral effect, but not to that extent that any member here should ever have to worry about. To top it off, the weapons used were bushmasters for Christ's sakes! Those pooping the ammo, are regurgitating hearsay, as I have not detected any noticeable accelerated wear or abnormal operating characteristics in any of my carbines that I haven't experienced with brass ammo, which is very little. The test was completely pointless in my opinion and duped the shooting community with erroneous information. If they would have used a military grade weapon shooting 10K rounds of Wolf over a one year period, as a typical member here would shoot, they would not have gotten those results. As always, it's your money and personal preference. YMMV and all that shit...
sinlessorrow
03-09-14, 12:38
In the IAR test the HK CHF barrel lasted several times longer than it's buttoned competitors.
Several times.
It is my understanding that they did not measure accuracy to test barrel life, believe F2S and I had a convo about this in an older thread.
Also my understanding the HK was the exception with their barrel outperforming other CHF barrels as well.
sinlessorrow
03-09-14, 21:08
What metric are you defining "barrel life"?
Throat and or port erosion?
Or still can sling bullets at 25-50m and hit close to POA? ala a useless IMO filthy 14 discussion.
Precision groups, still stabilizing, with (insert here your favorite) projectile at 300m (my metric)
With roughly the same firing schedule, in a training environment, 10" barrels, a MK18 barrel will do 7-10K and a HK416 10-12k before performance noticeably degrades.
Barrel temps, max and sustained, velocity and projectiles used clearly matter....
I haven't looked for or at any IAR data, but the HK M27 has a substantial barrel profile, a defacto massive heat sink with it's large barrel nut and long heavy aluminum rail. Test data showing exact firing schedule/ammo, and barrel temps would be useful.
My personal preference is accuracy at 100M. Once the groups are horrible its time to replace the barrel.
bingbangouch
03-10-14, 09:12
I don’t have any hard numbers but I was talking to a guy who has an M16 lower and he says there is a substantially noticeable difference in longevity between standard chrome lined barrel and CHF barrels.
I'd be more interested in bore diameter consistency than life. My guess is that a CHF barrel would be less prone to the bore diameter variances that button rifled barrels can suffer. But I'm not knowledgeable enough about the process to say this is true.
FYI: I'm selecting a barrel for an integral upper. That means barrel swaps will have to be done by the manufacturer. The upper will also be registered via the ATF. For a normal upper wear and tear may not be a big deal, but in the regulated world of NFA it becomes a bigger consideration.
CHF will last longer. What the argument is about is how much longer. Also as noted not all CHF barrels are equal. FN barrels outperform DD, and HK appears so far to be the best of the bunch.
CHF will last longer. What the argument is about is how much longer. Also as noted not all CHF barrels are equal. FN barrels outperform DD, and HK appears so far to be the best of the bunch.
The evidence to back this up?
Ammo choice more important than barrel?
http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/
Government trials are the best open source information you're going to get.
When the Marine Corps was originally looking to adapt the IAR they conducted numerous tests of barrel durability and through signifant amounts of testing found CHF barrels had significant longer barrel longevity.
What may be surprising to "gun guys" was the HBAR Colt barrels really did not have much longer of a barrel life than the control A4 barrels. While CHF barrels had much longer barrel life than non-CHF and has been pointed out H&K really knows how to make a barrel because theirs lasted 4x the non-CHFs and 2 x longer than other makers' CHFs.
You may remember back the M4A1 PIP one of the proposals was CHFs because they tend to last longer and sustain abuse better.
The problem with coming to conclusions with some of the tests that have already been done, is there are to many variables. To really test CHF against a non CHF, you would want the same profile, using the same steel, with the same amount of chrome lining, preferably from the same manufacturer, shooting the same ammo and the same rate of speed...ect. That way you are really testing just the one variable.
Most the barrels that I have owned have been CHF. Maybe it is a gimmick, maybe not. They are usually only a few bucks more. That being said, I am not sure I am going to be able to hold off the urge to get the new BCM ELW barrel until it comes out in hammer forged.
TurretGunner
03-11-14, 07:16
CHF is a gimmick. It is a METHOD of making a barrel, not some fandanged process or whatever.
There are plenty of JUNK CHF barrels out there, like ruger factory/ect.
The reason they use CHF, is its CHEAPER and QUICKER than any other method. The downside is it takes substantial capital outlay and you need to move vollume to see the real benefit (cost)
I'll take a Cut Rifles Bartlien or Krieger ANYDAY over a CHF whatever.
My chf barrels have all been great. I've never worn a barrel out, but I can tell you they are much easier and quicker to clean and don't hold copper.
I will tell you that from the cutlery industry standpoint, hot and cold hammer forging a blade into shape tends to make the steel more uniform and consistent. However, if you use a high quality steel with advanced smelting techniques, then forging the blade doesn't do any good since the steel is already uniform and consistent due to the crucible smelting process. Where hammering and folding of steel helps is when the steel is of lesser quality. From that perspective, I will say that if you CHF a barrel from lesser quality steel it should rival a button barrel of higher quality steel. However, if both barrels are made of very high quality steel, then the benefits would be negligible.
As I said look up a process called autofrettage; it has been done for almost 100 years to cannon barrels and it almost doubled cannon tube life
When the Marine Corps was originally looking to adapt the IAR they conducted numerous tests of barrel durability and through signifant amounts of testing found CHF barrels had significant longer barrel longevity.
What may be surprising to "gun guys" was the HBAR Colt barrels really did not have much longer of a barrel life than the control A4 barrels. While CHF barrels had much longer barrel life than non-CHF and has been pointed out H&K really knows how to make a barrel because theirs lasted 4x the non-CHFs and 2 x longer than other makers' CHFs.
You may remember back the M4A1 PIP one of the proposals was CHFs because they tend to last longer and sustain abuse better.
Not surprising... and exactly right on what R0N posted. The steel quality is important too, and it is one of the "secrets" (not really) of HK.
There are many reports of exceptional durability (measured as velocity loss, bullet stability decent accuracy) and even sustained high accuracy from HK barrels. The FN SPR rifles also managed to fire sub-moa (they say 0.5 MOA?) groups in the FBI tests after 10,000 rounds of match 308, try that with a button rifled barrel.
99% CHF machines used all over the world for small arms, all makers, come from ONE austrian maker. Not all of them are the same quality, but in general they tend to last much longer.
Not surprising... and exactly right on what R0N posted. The steel quality is important too, and it is one of the "secrets" (not really) of HK.
There are many reports of exceptional durability (measured as velocity loss, bullet stability decent accuracy) and even sustained high accuracy from HK barrels. The FN SPR rifles also managed to fire sub-moa (they say 0.5 MOA?) groups in the FBI tests after 10,000 rounds of match 308, try that with a button rifled barrel.
99% CHF machines used all over the world for small arms, all makers, come from ONE austrian maker. Not all of them are the same quality, but in general they tend to last much longer.
I guess the question is, would the HK MR556 non chrome lined barrel be considered a high volume, rapid fire barrel compared to other CHF barrels with chrome lining.
Chrome lining is more for corrosion protection than durability. The steels used in .mil contract HK rifles don't rust so easily and are very durable, don't know if they use other grade of steel in civilian guns. For a long time, many (most) HK military rifles were non-chrome lined, they only did it for large contracts by request of the buyer.
IMHO, as for all out target/match type accuracy like at Camp Perry or if you need FBI HRT type accuracy, cut rifled heavy barrels like Bartlien or Krieger, etc. will edge out the CHF barrels. All things being equal (barrel steel, twist rate, firing rate) I believe CHF barrels probably have a little more longevity. How much in number of rounds, who knows. As for accuracy, look at the damage Carlos Hathcock did with his Vietnam era rifles. I wonder what MOA they were cable of compared to todays rifles. Here is a link to a what LAV had to say about the CHF barrel process.
https://www.google.com/url?q=https://www.m4carbine.net/showthread.php%3F97781-Cold-hammer-forged-barrels&sa=U&ei=_U8fU9OwNaPC0QG1_IHwBw&ved=0CAYQFjAA&client=internal-uds-cse&usg=AFQjCNEs-TPxsqTKkab0WnRUP0wH6II6Aw
Heavy Metal
03-11-14, 13:08
Ammo choice more important than barrel?
http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/
You need to go back and read thru the thread. Already discussed.
or if you need FBI HRT type accuracy
Hey. No one is trying to kill women and children here.
sinlessorrow
03-11-14, 15:43
When the Marine Corps was originally looking to adapt the IAR they conducted numerous tests of barrel durability and through signifant amounts of testing found CHF barrels had significant longer barrel longevity.
What may be surprising to "gun guys" was the HBAR Colt barrels really did not have much longer of a barrel life than the control A4 barrels. While CHF barrels had much longer barrel life than non-CHF and has been pointed out H&K really knows how to make a barrel because theirs lasted 4x the non-CHFs and 2 x longer than other makers' CHFs.
You may remember back the M4A1 PIP one of the proposals was CHFs because they tend to last longer and sustain abuse better.
How was barrel life measured? Also interesting is Dano comment about barrel like on the HK416(10.3" BARREL).
Via erosion gauge, accuracy testing was done in another series of testing to compare free floating and non-free floating.
There was also a series of tests on the ergonomics of A4s, A4PIPs, M4s and M27s while conducting table 1, they compared both scores and shooters likes
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.