Cold Hammer forged worth the extra $$?

[SpentCasing]

Being an active duty SEAL is utterly meaningless regarding metallurgy. He might know what he's talking about regarding the subject - I won't argue against him - but being a SEAL is meaningless.

Of course, he also is selling a product. I have never met a man at a gun show selling a rifle that was not ultra accurate and ultra reliable. Of course his barrels are better than anyone else on the market.

So exactly which part is he wrong on? Which part is marketing and which is truth? All? None?

Im interested in which part he said was untrue and pure marketing... Heck, I dont even see his co. named in the quote at all. I mentioned his co. as well as his .mil experience. Not him. Hmmmm.. Sorry but Im not seeing the agenda nor conspiracy that hes steering ppl to buy Centurion CHF bbls. Seems hes sticking to facts based upon his experience.

Im sorry but Monty Leclair is hardly a gun show poser. His word carries a lot of weight on the subject vs. some random gun show dealer. Or some stranger that shoots dirt clods on the internet for that matter. What makes you a SME or even skeptical/educated on the subject? I ask only because I assume you have no affiliation with any company so your opinion must be unbiased, right?

 

[lysanderxiii]

A cold hammer forged barrel is not worth the extra cost. CHF was developed by the Germans to make a lot of barrels rapidly for less cost per unit than other manufacturing methods. In fact, the CHF process is one reason Remington was able to make bolt action rifles economically in the post war years.

Chroming the chamber and bore does help barrel life, but it's no better than the underlying material. A chromed barrel made of poor quality steel will still wear faster than a barrel made of good quality steel

Not necessarily, The Japanese in WW2 were forced, by lack of availability of good alloying materials, to make barrels out of inferior material. Oddly enough, they could get chromium and chrome plated the barrels made from marginal quality steel. Post war US tests on Japanese chrome plated bores showed that the barrel life was comparable to US small arms barrels that weren't lined at the time.

For this reason the US began to look at the benefits of chrome plating small arms bores, previously, we had thought that chrome was only worth it on big stuff, 16 in naval guns, and the like...

Or did you mean to say: "A chromed barrel made of poor quality steel will still wear faster than a chrome-lined barrel made of good quality steel"

If the above is what you meant, then yes, absolutely.

 

[lysanderxiii]

I prefer them.

Heres a quote from Monty Leclair over at Weapon Evolution. For those that dont know he is the owner of Centurion Arms and an active duty SEAL. ie: the definition of SME vs. some keyboard commando

Unless they changed the drawing recently, M240s and M249 barrels are made from MIL-B-11595 steel, which is the same as that call out for M16 and M4 barrels, the military version of 41V50 steel. The only major improvement to these is the stellite lined versions (I didn't think the M249 is stellite lined).

The US Army did a study on rotary forging (CHF) barrels back in the 1970s, here are some excerpts from the report:

Conclusions.
a. The rotary forging process is an improved method of manufacturing military small arms barrels.
b. Small arms rifle and machine gun barrels from .17 caliber to .50 caliber inclusive can be successfully rifled on the GFN Model SHK 10 Forging Machine.
c. Rifling and chambering, including simultaneous outside contouring, can be successfully achieved.
d. Rifling is best achieved between a 27% to 29% reduction in cross sectional area. Rifling with chambering is best achieved between a 37% to 39% reduction.
e. Precision sniper rifle grade barrel rifling occurs in a narrow range of machine settings. The extremes result in either "underfilling" of the lands (represented as rounded corners) or "overfilling" of the lands (represented as tearing or galling and will drastically reduce mandrel life.
f. Metallurgical analyses demonstrate that rotary forged barrels meet or exceed military requirements. Improved grain structure, increased toughness, better corrosion resistance, and finer surface finish result from the process. In general, the geometry and surface finish of the mandrel are reflected precisely in the barrel bore. Bore finishes of 8 micro inch (arithmetic average) or less are possible.
g. Rotary forged barrels exceed military accuracy requirements.
h. Bore variation is drastically reduced and straightness increased. Variations of less than .00015 inches are common.
i. Greater utilization of rotary forging for barrel production will occur when engineering design is more closely correlated to this process.
.
.
.
.
14. Benefits.
a. Any item in the Army Material Plan (AMP) that can be manufactured more economically and/or with better properties by rotary forging will benefit from this project. Military small arms weaponry will be greatly improved by the adoption of thin process. The benefits to the Government include: (1) reduced tooling and labor costs and increased production by using one forging operation for rifling, chambering, and exterior contouring, (2) metallurgically improved weapons due to finer micro-structure, (3) much higher production rates for difficult to machine super-alloy barrel materials required for rapid firing, weapon systems, and (4) the ability to produce extremely accurate small arms independent of operator skills.
.
.
.
.

Cold Rotary Forging of Small Arms Barrels, Arsenal Operations Directorate (AD A021 752), you can find the entire report on DTIC.

From that I read that the major improvements from CHF barrels is improved productivity and reduced cost for the same quality. It also implies that just because it is CHF, it is not automatically more accurate than a barrel well made in the traditional methods (see the bit about "sniper barrels").

 

[lysanderxiii]

To answer the question: "Cold Hammer forged worth the extra $$?"

Since the major advantage of a CHF barrel is reduced cost for comparable quality, I would expect that I shouldn't have to pay more $$$....

 

[NWcityguy2]

Ok. This always comes up in these threads too.

Basically if all you want is a report with a budget not short of a first world .gov ... It doesnt exist.

What you will find is a mountain of anecdotal evidence from SMEs who see and have more firsthand experience than most. And most of those top SME have businesses willing to sponsor them to offset their expenses in order to travel and share their knowledge.. Are they biased? Of course. Everyone has a bias. Are they flat-out shills? I believe not. But simply starting your own co. or being sponsored does not negate your knowledge as advertisement. If a well known SME is but a shill this industry is small enough that hed be called out in an instant. Yet all the top dogs seem to agree on a lot of points. CHF being more durable is one of many.

So my question is what do you want short of a .gov multi-year, multi million dollar study would convince you? If the answer is nothing... Well ok then. But Ill speak for "most of us in the know" and say the opinion and experience of a SME carries a ton of weight vs. Joe Blow. Good enough for a single individual? I dunno. Decide for yourself. But the evidence that there are advantages is fact and only someone willfully ignorant would choose to ignore it. Whether you will benefit from those advantages, therein lies the rub.

Now as for would xxx company's CHF machine be as good as yyy? IMO, yes. I would consider myself a SME in mfg and I would assume very few companies make the CHF machines. Ruger or Rem or FN aint designing it themselves. Theyre buying it from a certain company and having it installed. But Ill admit Im far from a SME on rifle bbl QC across the board.

You're still just name dropping. If they want to speak, then they can. You certainly weren't elected their spokesman.

Oh and FWIW, FN absolutely makes BCM''s CHF bbls. As well as Centurion, Spikes, PSA, Noveske, Rainier, etc. This is common knowledge.

You got a link for that?

 

[Ash]

Spent, being a SEAL has nothing to do with metallurgy. A tubby 55 year old machinist is vastly more qualified in the realm. A SEAL is mentally disciplined, in outstanding physical condition, and is fully capable of a number of highly specialized tasks.

He is not an engineer. The name-dropping worship here is getting silly.

But, as I said, "Being an active duty SEAL is utterly meaningless regarding metallurgy. He might know what he's talking about regarding the subject - I won't argue against him - but being a SEAL is meaningless.

Of course, he also is selling a product. I have never met a man at a gun show selling a rifle that was not ultra accurate and ultra reliable. Of course his barrels are better than anyone else on the market."

I have not attacked his product, only saying further proof is needed beyond being a SEAL as well as some doubt must always exist when a man puts his name on a product. A man hawking his wares is always suspect, even if he is telling the truth.

The barrels might be the best on the market, they might be the most reliable as well as the longest lasting. They may impart superb accuracy. But coming from a SEAL does not prove that.

Or, are Bear Grylls' knives and machetes the best on the market?

 

[bush3755]

It's interesting than anyone would claim all barrels are hammer forged. They must not be aware of the single-point cut rifled barrels that are becoming the favorite of competitors wanting best accuracy. And the broach-cut barrels where all grooves are cut in one pass of the broach through the gun-drilled blank; some of which have won matches and set records competing against cut and button rifled ones.

Button-rifled ones may be thought to be "reverse hammer-forged" as the metal's pushed out from the bore diameter; opposite that of external hammers forging a bored blank on an internal mandrel.

 

[RugerOldArmy]

The most compelling point on CHF barrels, to me, was the point about tapering the bore. That has been proven to positively impact accuracy. On the downside was this point on CHF barrels.

Precision sniper rifle grade barrel rifling occurs in a narrow range of machine settings. The extremes result in either "underfilling" of the lands (represented as rounded corners) or "overfilling" of the lands (represented as tearing or galling and will drastically reduce mandrel life.

Sharp smooth lands increase accuracy.

Chrome lining? A reduction in accuracy.

I'm on Jackal's side, in terms of wear...it is not an issue. Barrels, like tires, can be replaced. Before they are, get my bullet to where I aim it.

Personally, I'll take a Kreiger cut-rifled barrel, without chrome lining, as a top choice...in a heartbeat. Find a way to taper that bore slightly narrower near the muzzle, and I'll be even happier.

Chrome lining and wear concerns are most appropriate for a battlefield. For most all of the posters here, it should all be around the size of the groups downrange, IMO.

 

[bush3755]

From what I've gleaned from people getting best accuracy across all shooting disciplines, single-point cut rifled barrels seem to be the favorite these days. Button rifled ones were great for decades, but have slipped a bit in popularity recently. And some broach rifled barrels have equaled the accuracy of cut and button rifled barrels

Both the .223 Rem and .308 Win cartridges seem to have about a 3000 round barrel life for best accuracy in those starting out that way in the sub 1/4 MOA at short range. For service and combat use, 10,000 rounds is good enough to keep them inside a few MOA at 100 yards.

Regarding the grain structure of hammer forged barrels; I doubt it has any significant difference in a barrel's vibrating patterns compared to other rifling methods. No such entry is used in the finite element software used by mechanical engineers calculating hollow round bar stiffness, rigidity and vibrating characteristics in the 4th order math used that I know of. If there is a difference, I think it's buried in the details more easily measured.

The US military sniper rifle specs for accuracy is not what I would celebrate. At least by the specs stated in MIL SPEC documents available for public vewing.

 

[lysanderxiii]

The most compelling point on CHF barrels, to me, was the point about tapering the bore. That has been proven to positively impact accuracy. On the downside was this point on CHF barrels.

Sharp smooth lands increase accuracy.

Chrome lining? A reduction in accuracy.

I'm on Jackal's side, in terms of wear...it is not an issue. Barrels, like tires, can be replaced. Before they are, get my bullet to where I aim it.

Personally, I'll take a Kreiger cut-rifled barrel, without chrome lining, as a top choice...in a heartbeat. Find a way to taper that bore slightly narrower near the muzzle, and I'll be even happier.

Chrome lining and wear concerns are most appropriate for a battlefield. For most all of the posters here, it should all be around the size of the groups downrange, IMO.

If you read the drawings for the USGI M16 barrel, they state that:

Notes:
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.
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9. Bore and groove diameters shall be within the dimensional limits specified and, when measured from the chamber end towards the muzzle end, shall meet the following requirements:
1. diametral reduction of the bore and groove diameters shall be .0001 dia max for length -A-.[length -A- is the last 1/4 in at the muzzle]
2. no bore diameter shall be more than .0004 larger than the smallest previously measured bore diameter.
3. no groove diameter shall be more than .0004 larger than the smallest previously measured bore diameter.
.
.
.

So, no M16 barrels have a maximum reverse taper more than 4 ten-thousands and must be at least cylindrical to a .0001" positive taper at the muzzle.

M14 National Match barrels specifically state:

18. The bore diameter shall not vary more than .0003 in the length of any barrel. The groove diameter shall not vary more than .0003 in the length of any barrel. In no case shall the barrel bore or groove diameter be larger at the muzzle end than at the chamber end and any taper shall be diminishing from the chamber toward the muzzle.

Really, it is just a matter of gauging the barrel blank and picking the large end as the chamber end.

 

[HKGuns]

Boy is there a ton of misinformation in this thread.

Better? Depends on what you want..........

The most accurate? - I'm pretty sure the most accurate barrels are typically NOT CHF and are used up after ~1500 rounds. Does this mean a CHF barrel isn't accurate? Nope. It means use the right tool for the application.

Longer life and durability? - Probably worth the extra $$, assuming a good grade of steel is used in the CHF process.

The CHF machines are not cheap. It is only cost effective if you have the ability to produce and sell large quantities. Otherwise, it is a waste of $$ to CHF which is why you see large military contractors (FN - HK - etc..) and Ruger producing CHF barrels. They wouldn't be using it if it wasn't cost effective and produced a superior product for the application. Regardless of what those, who have never dreamed of owning a business think.

 

[RugerOldArmy]

So, all M16 barrels have a maximum reverse taper more than 4 ten-thousands and must be at least cylindrical to a .0001" taper at the muzzle.

Really, it is just a matter of gauging the barrel blank and picking the large end as the chamber end.

Or were they talking about testing lots/batches of barrels? I don't believe they were talking about measuring just past the throat, and at the muzzle.

There is also a tendency, on the internet, to hold up Milspec, as a standard of quality.

In terms of accuracy, it isn't. Look at the 5.56 NATO chambers. They aren't designed for accuracy.

 

[bush3755]

I'm not aware of any barrel maker catering to match winners and record setters getting best accuracy taper the bore/groove diameter down from breech to muzzle. They're all about .0001" tolerance from throat to muzzle.

It would be difficult and time consuming to make the taper smooth, straight and without any irregularities.

 

[Jim Watson]

Choked or tapered barrels were desirable in lead bullet days. They worked for Harry Pope and several of his contemporaries and predecessors.
Pedersoli says their .45-70 barrels are tapered, which has to be a good trick since they are broach rifled.

You will see some target rifle barrels, mostly .22s, with a larger diameter section for several inches at the muzzle. Some say it is to tune the harmonics, some say it is for a muzzle heavy offhand hang, but it is also to generate some choke. Button rifling a cylindrical barrel blank leaves a lot of residual stress, some even after stress relief heat treatment. Turn the barrel to a contour and those stresses show by expanding the barrel where the most cutting is done. Leave the muzzle end thick and leave it the smallest I.D. which is desirable for lead bullet accuracy and avoids a flare which is damaging to accuracy with about anything.

Gain twist rifling was also popular in the lead bullet era, and sees some use now. An increasing twist rate as you go down the barrel keeps the bullet "tight" and serves somewhat like a choke. Bartlein will make you a barrel with any progression of twist you like. Akin to those heavy muzzled .22s, they also sell a small gain from 16.5 to 16 to be absolutely sure there is no reduction at the bullet exit.

 

[RugerOldArmy]

They worked for Harry Pope and several of his contemporaries and predecessors.

You're well read Jim Watson. I'm proud of you.

I could be wrong, but I seem to remember it as a Holland and Holland feature too. One of the English makers.

I'm not sure it would only help with lead projectiles.

 

[lysanderxiii]

Or were they talking about testing lots/batches of barrels? I don't believe they were talking about measuring just past the throat, and at the muzzle.

There is also a tendency, on the internet, to hold up Milspec, as a standard of quality.

In terms of accuracy, it isn't. Look at the 5.56 NATO chambers. They aren't designed for accuracy.

Did I say it was better? No, you asked to:

...[f]ind a way to taper that bore slightly narrower near the muzzle, and I'll be even happier...

And, I stated that a Mil-Spec M16 is tapered at the muzzle, but not necessarily tapered the entire length toward the muzzle.

NM M14 barrels were required to be tapered toward the muzzle, if there was any measurable taper. The point was to show the difference between match barrels and service barrels

Any quality match grade barrel priced at $350 or higher better be air gauged, or similar, for dimensional conformance its entire length, it's a fairly quick check, 1) so they know if the bore and rifling are up to snuff, and 2) so you know which end should be the chamber, if you can detect a taper...

OH...

It would be difficult and time consuming to make the taper smooth, straight and without any irregularities.

With cold rotary hammer forging, you can. You can do almost anything you want except gain twist rifling in a rotary hammer forge. The Germans did it in the 2.8 cm Panzerbüchse 41 (2.8 cm sPB 41), and the 7.5 cm Pak 41, The 2.8 cm sPB 41 has a rather sever taper starting at 28mm at the throat and 20mm at the muzzle, the 7.5 Pak 41 had a taper of 75mm at the throat and 55mm at the muzzle.

Obviously there was much deformation of the projectile....


Not cold rotary hammer forging, but rotary hammer forging a 120mm gun tube, same principle, just that the work starts out hot....
https://www.youtube.com/watch?v=QtqwlgEC-bg

 

[minutemen1776]

There is also a tendency, on the internet, to hold up Milspec, as a standard of quality.

Indeed. Since CHF is not on "The Chart," it is utterly worthless. That should end the discussion.

 

[MistWolf]

...did you mean to say: "A chromed barrel made of poor quality steel will still wear faster than a chrome-lined barrel made of good quality steel

Yes, this is what I meant