View Full Version : Cold Hammer Forged or not?
JSTICFRALL
08-02-10, 13:14
I'm thinking about getting this upper receiver from BCM (http://www.bravocompanyusa.com/ProductDetails.asp?ProductCode=BCM-URG-MID-16%20DDL12) but can't decide if getting the hammer forged barrel option is completely worth the extra $100. Where will I see the advantage? I know the hammer forged option is stronger, but will someone like me (who shoots paper, wants a good weapon for when the shtf, and would like to do carbine courses in the future) ever see my extra $100 be put to good use?
ForTehNguyen
08-02-10, 13:18
if you plan to shoot a ton of rounds per year then the hammer forge is worth it due to the barrel life. How many rounds do you expect to shoot per month or per year. Standard barrels can last 10k rounds, hammer forge 2-3x that.
JSTICFRALL
08-02-10, 13:22
I shoot about 200 rounds when I go to the range because I can't afford to shoot more at this time. I would like to go at least once a month when I get my new build together.
If you have the $100.00 to spend, and it isn't a big deal; go for it. IF you won't be able to afford ammo or food for the next week, keep the $100.00 and go for non-hammer forged. You'll see extra life from a CHF barrel, but CHF doesn't change accuracy or reliability (Until you get close to shooting out the barrel, then reliability becomes and issue, but that is after tens of thousands of rounds, if not more). You could always save the $100.00 and use it for ammo or training, and then if/when you need a new barrel (Very doubtful if you are just a recreational shooter that shoots 1,000 rounds and less a year) you can just buy a CHF one then.
I would opt for the CHF barrel personally; no reason to delcine getting more life out of a barrel if cost is not a big issue...
Don't sweat the decision too much, they are both great barrels and will last a long ass time. :cool:
100 bucks is not much in terms of a rifle build which often costs 2,000 once you include the optic (ACOG? over 1K sometimes, Night Force in the range of $1500), mount (Larue 125), rail (300 or more?), match BCG (205), fancy trigger (170-350), fancy buttstock (UBR 225), fancy brake (150), good LPK ($80), nice grip ($40), rail covers (?), Troy flip up sights ($240), tritium front sight insert ($50), special buffer ($40 on up), etc.
JSTICFRALL
08-02-10, 13:38
Well I've been trying to set my budget at right about $1k for my new upper. Not to mention I'm gonna have to buy a front BUIS since I don't have one and the upper doesn't have a front sight post. So that right there is gonna put me at $1k after shipping and all that. Also I guess by the time I shoot out the barrel I'll (hopefully) be in the position where I can spend a couple hundred bucks on a new CHF barrel and keep shooting for another 10 years. As long as there is no compromise in accuracy then I can live with the non CHF option. Times are tight but I gotta keep shootin!
ForTehNguyen
08-02-10, 13:40
ive read its a YMMV on accuracy improvements? Never really seen it quantified. I've never had direct experience with a CHF. I dont shoot enough to justify the CHF for a barrel life standpoint.
Wasn't Pat Rogers' "filthy" BCM a 16" hammer forged barrel that still shot MoA after 25,000+ rounds?
As 500 gr mentioned, when you consider the additional cost in the total cost of the rifle, it's not that high, and if you can afford it, I'd say go for it.
ive read its a YMMV on accuracy improvements? Never really seen it quantified. I've never had direct experience with a CHF. I dont shoot enough to justify the CHF for a barrel life standpoint.
I've heard this as well, but haven't seen any real world evidence of it. I have one of the first few DD M4 V1's to be built aqnd sold and it has a non-CHF barrel; I will just replace it with CHF when the time comes. I have (3) buddies with the same DD M4 V1, but the newer CHF barrel, I out shoot all of them with my rifle, and I see no difference in my accuracy whe I try out their rifles.
Anyone done any real hard-use comparisons? Such as pushing multiple non CHF and multiple CHF barrel to the 10K mark and seeing if the non-CHF has any noticeable decrease in accuracy Vs. the CHF barrel? Sounds like an interesting test I would like to see performed. I wouldn't be surprised if the CHF barrel held accuracy better than the non-CHF approaching the higher round counts, but not sure if it would even be that much of noticeable or problematic decrease?
if you plan to shoot a ton of rounds per year then the hammer forge is worth it due to the barrel life. How many rounds do you expect to shoot per month or per year. Standard barrels can last 10k rounds, hammer forge 2-3x that.
I've seen the 10~15k barrel life # tossed around. Is that based on semi-auto or military F/A type usage?
JSTICFRALL
08-02-10, 14:34
Good question...also is it the heat cycles or is it the friction caused by the bullet that causes a barrel to lose its life? Probably a combination of both?
CHF for me. And to be specific, a CHF DD lightweight (.625"approx) profile 14.5" mid-gas barrel.They should be out in the next 3 weeks.
I've seen the 10~15k barrel life # tossed around.
A fellow at Sabre Defence told me they expect their milspec chrome lined M4 barrels to run 35,000 rounds. And those are button rifled, not hammer forged.
I wonder what the true barrel life is for a Noveske with a hammer forged barrel made from M249 barrel steel. 100,000 rounds? Should be the same for a Centurion barrel.
Good question...also is it the heat cycles or is it the friction caused by the bullet that causes a barrel to lose its life? Probably a combination of both?
A lot of barrels sustain more damage due to sloppy use of the cleaning rod than from bullets.
Failure2Stop
08-02-10, 17:04
Good question...also is it the heat cycles or is it the friction caused by the bullet that causes a barrel to lose its life? Probably a combination of both?
High heat+high friction=accelerated wear.
Grease Monkey
08-02-10, 18:47
Wasn't Pat Rogers' "filthy" BCM a 16" hammer forged barrel that still shot MoA after 25,000+ rounds?
As 500 gr mentioned, when you consider the additional cost in the total cost of the rifle, it's not that high, and if you can afford it, I'd say go for it.
Ok, Filthy 14 is a standard BCM 16" middy non CHF. currently has approx 32,000 rounds through it. I don't know about the moa part.
CHF is NOT necessary for most.
Good question...also is it the heat cycles or is it the friction caused by the bullet that causes a barrel to lose its life? Probably a combination of both?
Hot gasses only. The chrome lining is far harder than the bullet jacket.
I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?
As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?
I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...
Cameron
Jake Bauer
08-02-10, 23:54
I'm glad i got a CHF barrel. I dont shoot a lot either but it's good to know it will last a very long time and they can handle really high volume shooting.
I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?
As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?
I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...
Cameron
Well thought out and stated and I would really like to see this answered as well.
GermanSynergy
08-03-10, 11:13
OP,
Just my opinion, but I would save up and get the CHF barreled upper. It has zero drawbacks and many benefits should you decide to train more in the future.
YammyMonkey
08-03-10, 13:42
Cameron pulled the thoughts right out of my head.
Thomas M-4
08-03-10, 14:04
I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?
As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?
I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...
Cameron
Hard chrome is harder than the steel so it last longer. But just because it is harder doesn't mean it will not wear out it just takes longer. If you have x2 chrome lining you are going to have 2x more to go through before you get down to steel.
CHF barrels are denser because they are hammer forged the rifling, chamber, throat are all forged, The forging also hardens the steel.
Look what been done to GPMG for extended barrel life thicker chrome lining higher grades of steel hammer forging [originally develop by the Germans in WWII for mass production of MG-42 barrels].
Look up Stellite-lined barrels cobalt steel lined chamber and throat.
Cant be much good for accuracy but I am sure it would laaaassst.
Not the best explanation but i hope it helps.
Hard chrome is harder than the steel so it last longer. But just because it is harder doesn't mean it will not wear out it just takes longer. If you have x2 chrome lining you are going to have 2x more to go through before you get down to steel.
I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value. Once you've worn through the standard thickness of the chrome, yes you would still have more hard chrome before you got to the steel but you've still worn the barrel to the point the ID is no longer the same, thus degraded accuracy. Which would then beg the question, what's the point of the harder cold hammer forging or the 2x chrome lining?
ETA: I may be way out of my lane here. I'm not an expert gunsmith or metallurgist but I have stayed at a Holiday Inn express before:D
JSTICFRALL
08-03-10, 16:15
I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value.
I was thinking the same thing. So would the CHF barrel be more beneficial if it wasn't chrome lining? Cause then the bullet would be having direct contact with the hardened steel and not a chrome coating. I would assume that once the chrome lining has been worn through, no matter what material the barrel is made of, the barrel has then lived its life and accuracy will begin to suffer.
...or is the strength of the rifling what makes the life of the barrel, chrome lined or not?
There's so many dang variables to this:confused:
Thomas M-4
08-03-10, 16:36
I'm not sure how a hammer forged barrel outlasts a standard barrel if they are both chrome lined. The heat and friction will eventually wear away the chrome lining, so isn't the hardness of the chrome the relevant component of barrel life?
As the chrome is worn away the rifling has a less consistent contact with the bullet and you get a degradation is accuracy. The rifle with still work the groups just open up?
I also don't understand how chrome lining that is twice as think (Noveske) would make a difference. If the rounds wear the chrome lining a measurement of X wouldn't both barrel standard chrome lined and double thickness chrome lined now have the same amount worn? They had to have the same interior dimensions to to start with and in both cases the bullet wears the same amount of chrome, so the interior diameter would be the same...
Cameron
I don't like to speak for others but I think what Cameron was getting at and my question as well is even though you have 2x as much hard chrome, the inside diameter of the barrel is still a set value. Once you've worn through the standard thickness of the chrome, yes you would still have more hard chrome before you got to the steel but you've still worn the barrel to the point the ID is no longer the same, thus degraded accuracy. Which would then beg the question, what's the point of the harder cold hammer forging or the 2x chrome lining?
ETA: I may be way out of my lane here. I'm not an expert gunsmith or metallurgist but I have stayed at a Holiday Inn express before:D
You have an acceptable rate of wear that is what a throat erosion gauge is for. Will it still shoot bug eye groups no.. But we are not bench rest shooting neither. Example a few years ago a picked up a MK4 SMLE you can stick a .303 bullet all the way flush to the crown pretty dang wore out and it was also pitted. It would still group 5-8 MOA but it wasn't tumbling the bullets not the best accuracy by any mean. Just trying to point out that it still had some usable life has a spin stabilized bullet spitter. Not that I would want to take anything in that condition into harms way.
Failure2Stop
08-03-10, 16:54
Cameron has raised a pretty common point when discussing various barrel steels and those different steels when chrome-lined to various thicknesses.
All I have to offer is that which was passed to me by others in the industry- not by personal testing or verification, and have been relegated to dark and dusty corners of my memory.
What I recall from the discussion is as follows:
The thicker the chrome lining the longer it will take erosion, wear, and heat to expose the bare metal beneath the lining. The chrome lining is very thin, even in "double thickness" barrels. Loss of chrome from certain parts of the chamber and throat, while noticably detrimental to high-precision sub-MOA applications, will be transparent to single-digit MOA applications (such as those relevant to a "fighting" AR).
The harder the underlying metal is, the less the chrome will wear due to heat and friction, though erosion will always be present. Loss of chrome will start at the throat/leade, with decreasing levels of wear the closer to the muzzle you examine. This makes sense when you think about what is happening to the bullet in the barrel at these points. As the bullet engages the rifling it is being mushed by the lands, engaging them with the jacket. As the bullet continues to be pushed by gas expansion the "tracks" of the lands have already been inpressed into the jacket, so now the lands are simply guiding the bullet through existing tracks. Wear at this point is more focused on the edges of the lands than the flats of the lands. Once again, the harder the underlying steel, the less flex will be applied to the surface lining.
There is also a reasonable point that CHF barrels exhibit more consistent harmonics, including under high heat conditions.
Another issue is reliability, which really comes down to port erosion. The tougher the steel, the longer it takes for erosion to compromise the gas port.
Anyway, that's my understanding. I may have left better explainations out, but I did my best to convey my understanding of a topic that isn't really inside my area of expertise.
variablebinary
08-03-10, 16:59
The best thing about people jumping on the CHF snake oil bandwagon is lots of great deals on button rifle barreled uppers.
Are there concrete examples, rather than anecdotal, of the CHF barrels lasting longer? I agree with the post above about the extra chrome and the other advantages of the forged barrel.
Thomas M-4
08-03-10, 17:39
Are there concrete examples, rather than anecdotal, of the CHF barrels lasting longer? I agree with the post above about the extra chrome and the other advantages of the forged barrel.
Its been used in Europe for 50+ years.
First use was making MG-42 barrels MG-42 were rated at 1200 RPM. It was noted by the Germans that the barrels lasted longer. Not to mention they could make them faster. Than with traditional method's at the time. The MG3 is still made with a CHF barrel, The M-240 has a CHF , The M-249 has a CHF barrel , The AK has a CHF barrel alot of modern military fire arms use CHF barrels.
CHF barrels are denser because they are hammer forged the rifling, chamber, throat are all forged, The forging also hardens the steel.
If you are not rearranging protons and neutrons into different elements, you are not changing the density of the steel. Hammer forging it not rearranging protons and neutrons. It is hardening the steel and changing the grain structure/alignment.
Heat treat that results in phase changes, like quenching steel, can change the density.
Thomas M-4
08-03-10, 18:29
If you are not rearranging protons and neutrons into different elements, you are not changing the density of the steel. Hammer forging it not rearranging protons and neutrons. It is hardening the steel and changing the grain structure/alignment.
Heat treat that results in phase changes, like quenching steel, can change the density.
First let me say not a metallurgist :jester:
Its been used in Europe for 50+ years.
First use was making MG-42 barrels MG-42 were rated at 1200 RPM. It was noted by the Germans that the barrels lasted longer. Not to mention they could make them faster. Than with traditional method's at the time. The MG3 is still made with a CHF barrel, The M-240 has a CHF , The M-249 has a CHF barrel , The AK has a CHF barrel alot of modern military fire arms use CHF barrels.
Ok, this I knew, I was just hoping I wasnt out of line posting that.
Thomas M-4
08-03-10, 18:43
Ok, this I knew, I was just hoping I wasnt out of line posting that.
No not out of line perfectly reasonable question IMHO.
I was just trying to explain the variety of different military weapons that use the CHF barrel manufacturing method.
No not out of line perfectly reasonable question IMHO.
I was just trying to explain the variety of different military weapons that use the CHF barrel manufacturing method.
All of which have high volume in a short time frame in mind.
Colt Canada (then Diemaco) has used CHF barrels in their C7 (M16) and C8 (M4 like) systems for over 20 years.
20,000 rds life span has been achieved on barrels that where shot at a low to moderate rate of fire.
Hk, FN, and many other companies have used CHF barrels in rifles, as well as wait for it, most pistol barrels.
Jay Cunningham
08-03-10, 19:09
You need to make the determination for yourself, OP.
It sounds to me like a cold hammer forged barrel will not make any difference to you other than lightening your wallet a bit more.
Grease Monkey
08-03-10, 20:23
You need to make the determination for yourself, OP.
It sounds to me like a cold hammer forged barrel will not make any difference to you other than lightening your wallet a bit more.
Well put.
JSTICFRALL
08-03-10, 21:34
You need to make the determination for yourself, OP.
It sounds to me like a cold hammer forged barrel will not make any difference to you other than lightening your wallet a bit more.
Well in all honesty I want to know that I'm putting good money into a quality weapon. If that means spending an extra $100 to do it right, then I'll spend it. The whole reason why I was asking if it was worth it is because I know there are a lot more people on here that are more knowledgeable on the subject. Unfortunately since I don't have tons of money right now, this is going to be my only AR for a while (trust me the BRD hit me a long time ago when I got my first setup together). From the different arguments being made, it definitely seems like CHF is going to be the way to go. It's the direction I've been wanting to go in since I've been shopping for a new upper but I figured if I could go non-CHF and put that $100 towards an optic or ammo, I would. Lots of great info here and I feel a lot more educated thanks to you guys. Thanks!
Jay Cunningham
08-03-10, 21:38
From the different arguments being made, it definitely seems like CHF is going to be the way to go.
For who? The military? Possibly - they have a mission requirement that CHF can help meet.
It's the direction I've been wanting to go in since I've been shopping for a new upper but I figured if I could go non-CHF and put that $100 towards an optic or ammo, I would.
I think this is wise, in your case.
Thomas M-4
08-03-10, 21:57
To the OP the only CHF barrel I own is a POF G-3 barrel that is waiting parts to finish the build. My LMT still has its factory barrel and I have no immediate plans to replace it. I will probably pick up a CHF barrel later on when I am fairly certain that I am at least half way through the LMT barrel life first and then it will be stored away until the day it needs replacement. If it is between a CHF barrel and having the extra $$ for a good duty optic pick the optic for sure. There are plenty of good mil spec 5.56 chamber , 4150 cmv barrels out there LMT being a good example BCM being another.
variablebinary
08-03-10, 22:01
CHF is a very European process. It was the Germans that popularized CHF barrels to make machine gun barrels of good quality, faster and cheaper for two reasons
1: Machine guns burn out barrels faster, obviously
2. When someone is bombing the shit out of your military industry, getting barrels made fast is sorta important, because you never know when something explosive is going to crash through your roof.
We have plenty of beat to shit, shot to hell M16A2's in our armory. The last one I shot still makes scary tight groups with no effort.
CHF barrels are just a choice. Options are good, but many believe and have been convinced that CHF barrels are something they actually aren't when compared to a standard Colt M4A1 barrel
Cincinnatus
08-05-10, 15:02
I've seen the 10~15k barrel life # tossed around. Is that based on semi-auto or military F/A type usage?
In LMT's 2009 catalog, they claimed a barrel life of 10,000 rds average for their CL barrels. There is a thread about Noveske Barrel life here: https://www.m4carbine.net/showthread.php?t=54614
It has info on how long CHF barrels last.
buckshot1220
08-05-10, 15:58
From your last post I am not sure that you have actually made a decision yet, so maybe this will be of some help. I own both a BCM 14.5" std. (car. gas) and BCM 16" CHF (mid. gas). Using a host of different ammo (including MK262 clone handloads) I've been able to get the 14.5" down to right at MOA, 16" CHF I can get down to .70-.75 MOA. Groups were not shot on the same day and I don't keep weather logs, but I can say that both days were similar temps without any crazy humidity or precipitation. Both use FF rails and Aimpoints, T-1 and M4 respectively. This doesn't mean that one is more accurate than the other in respect to the rifling process since there is a difference in length of barrel, gasport location, size of aiming dot, different triggers etc.
So if I've managed to confuse you any more, your welcome:D
Basically, if the barrel contour you want is available in CHF and the extra $100 isn't an issue, go for it. If you are going to settle on a barrel contour just to get the CHF, then in my eyes it isn't worth it.
JSTICFRALL
08-05-10, 18:20
I was looking into CHF as a means of "preventative measures" if that's even the right term to use. I figured I should just go ahead and get the new upper with it now and not have to worry about replacing a barrel anytime in the near future. But then again if the average barrel life is 10,000+ rounds I'm starting to think I'll be okay with the regular CL.
OP, define your purpose & requirements and select equipment that meets them. If the advantage of CHF barrels meets your requirements and purpose then that's what you should be buying. The definition of quality is adherence to requirements, not goodness or elegance so don't fall into that trap.
JSTICFRALL
08-05-10, 22:28
OP, define your purpose & requirements and select equipment that meets them. If the advantage of CHF barrels meets your requirements and purpose then that's what you should be buying. The definition of quality is adherence to requirements, not goodness or elegance so don't fall into that trap.
I think that's the best way it's been put.
Those interested should speak with Mike Rock.
CHF has more densely compacted grains so it's stronger in many respects. It also has better wear resistance.
The substrate (underlying steel) material will be more stable than cut rifling and SHOULD offer a better grade base material than cut rifled material.
BTW, ferritic nitrocarburization is better than hard chrome: no geometric distortion, better wear resistance, better salt water corrosion resistance.
Combine the two: CHF and Melonite.
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