SS -vs- steel barrels

[BoogieMan]

In rebarrel the advantage of ss is that it requires no further finishing. Other than that 4130 (or other chro-mo) versus 400 series stainless barrels.
Which one wears better? I would think that the SS resists heat better than steel but it is a softer material. Does one tend to be more accurate than the other when floated? In particular I am talking about Rem varmint contour in a 6.5x47, 26" barrel. But, would also like to know as a general statement.

[jdscholer]

I'm also interested in this. Seems like my addled memory recalls that the new (at that time) stainless barrels extended the life of rifles like the 220 swift, and other barn burners of the day. Could be though that the carbon steel of the day wasn't up to the standards of our modern chrome-moly blends.

It's pretty common knowledge that stainless is softer than these carbon steels, but maybe the magic of stainless also protects it from fire erosion. I'd love to hear from a "real expert", not just the opinion of a layman like myself. jd

[Bart B.]

Go to Kreiger and Lilja barrel's web sites then see what they have to say.

I'm not an "expert;" those folks are.

Search "stainless or chrome moly rifle barrel" and you'll see some good information.

[Shooter2675]

If you go to a high power match chances are the majority of guns will have stainless steel barrels. I am no expert and don't know why they use stainless over chrome moly but it must be some sort of accuracy difference.

John

[dahermit]

It's pretty common knowledge that stainless is softer than these carbon steels...

Is it "common knowledge" by people who have access to a Rockwell hardness tester and have actually tested them for a significant difference? Maybe someone with that common knowledge will post the Rockwell C scale numbers. Unless you meant to say, "a common rumor was..."

[pwillie]

I have used Hart SST matchgrade barrels for over 18 years,and they are as accurate today as they were then...

[BoogieMan]

Is it "common knowledge" by people who have access to a Rockwell hardness tester and have actually tested them for a significant difference? Maybe someone with that common knowledge will post the Rockwell C scale numbers.

440 SS depending on condition A,B,C ranges from 20-60 Rc
416 SS """" up to Rc - 41
4130 steel (chro-mo) """"Rc 20-44
1045 steel Rb 88
4140 steel (chro -mo) """"Rc 25-60
Think is that hardness is a small function in this use. AR400 (armor plate) is not hard but its very abrasion and puncture resistant. If it was all about hardness and rigidity I could have a tungsten carbide barrel made and have it last forever, dont think its ever been done. SS in general has much better heat resistance and chemical resistance.
I couldnt find any information from barrel manufacturers on the subject.

[dahermit]

I could have a tungsten carbide barrel made and have it last forever...

Forever, until you fired the first shot...Tungsten Carbide is very hard, but like many hard materials, the hardness comes at the expense of being brittle. Gun barrels have to have some toughness.

[Bart B.]

I've not observed any accuracy difference between barrel metals as long as the hole in them has the same dimensional specs and tolerances. They'll both engrave the bullets the same.

Why wouldn't they?

[chris in va]

Why wouldn't they

Barrel whip, for one. A softer metal tends to flex more. Watch a slo-mo vid of an AR vs AK sometime.

[Bart B.]

All barrels whip, wiggle and vibrate very repeatable at their resonant and harmonic frequencies. Sometimes a greater amplitude of a less rigid barrel at the right frequency enables better accuracy at target range. The opposite could reduce accuracy, too. It's all about where in the muzzle axis' whip angle the bullets leave at.

[joed]

The only experience I have is having a Remington 700 VS rebarreled with a Krieger a few years ago. I remember telling the rep I wanted steel as the gun came with. He said SS. Once again I asked for steel, again he said SS. He said it twice and I figured he knew more than me.

So now I have an old Remington 700 VS with an SS barrel. It shoots like no other rifle I own. He did tell me it would outlast the steel but I do not remember everything he told me. When someone that builds rifles for a living tells me what I want I'll listen.

[joed]

I'll also add that ever since the day the rifle builder told me to go with SS all my new rifles are ordered in SS. On the other hand I have nothing against blued steel but prefer SS.

[Jimro]

Point 1: The material used does not determine whether a barrel will shoot well or not.

Point 2: The material used does determine how easy it is to machine.

Point 3: The easier it is to machine, the easier it is to make uniform. This also means the easier the material is to the mechanical/chemical wear factors of firing the rifle.

Point 4: It is easier to machine some grades of stainless steel than it is to machine some grades of ordnance steel.

Point 5: You can't tell the barrel material from comparing holes in a target.

It isn't that stainless is more acccurate than chrome-moly. It is easier to make a high quality single cut stainless rifled barrel than it is to make a high quality chrome-moly rifled barrel using that specific technique.

That being said, Anschutz barrels are button rifled chrome-moly, and there is a saying in air rifle and small bore "Shoot an Anschutz or lose to one."

You can make a very accurate barrel from any reasonable material using single point cutting, button rifling, or cold hammer forging. But since most custom rifle barrel makers don't have the funds to set up a cold hammer forging operation, you don't see them on custom built rifles very often.

Shilen makes button rifled barrels, and as far as I know still holds the most records for 200 yard and under benchrest wins.

Krieger, Bartlein, and others make cut rifled barrels, and they are definitely preferred by the long range target and tactical crowd. They are "stupid easy" to get to shoot well.

In the end, sometimes it's the indian, not the bow.

Jimro

[handlerer2]

OK, I'm going to take a stab at a plausible theory.

Decades ago, I was employed as a marine electrician, at Litton industries, Ingalls shipyard. I observed while doing ripouts on aging fast attack subs. A huge hole was cut through the hulls to rip out reactor. The pressure hull was chrome-moly eight inches thick. My uncle was the Yard Superintendant of machinists.

I was told that the steel used, was used for its property of elasticity, not hardness. I also learned doing a hot job on the USS Saratoga, the exhaust headers of which are made of CM, that CM has to be heated to almost red hot to be welded. That was what I was doing, monitoring the thermo-couplings. So CM has desirable thermal properties also.

The pressure hull has to go from sea level to a classified number of atmospheres of pressure, and back countless times reliably.

It's kind of a leap, but I think this property could have a reverse application. A rifle barrel has to go from ambient atmospheric pressure, to how ever many atmospheres all the CPU's convert to. Then it has to snap back to its initial state for the next cycle. It has to do this how many times?

Most earlier stainless steels were too brittle to be suitable for rifle barrels. I have a feeling considerable study was done on this modulus for specific properties and found some that worked.

I have rifles with both barrel types. My most accurate is a SS barreled Cooper MDL 22, 6.5x284, but I can't make a fair comparison, because my main hunting rifles are CM, Weatherbys, MKV and Vanguard are both, in my estimation are quite accurate.

The topic made me think about this, what think the rest?

[BoogieMan]

I started the conversation because Im a machinist and recently contacted Krieger about a barrel. I found out that there is no difference in price between the 2 when buying from krieger. To me the draw of a SS barrel in this case is that I dont have to finish it. As someone who has cut a variety of steels (not much chro-mo) and specializes in SS I can tell you that with the exception of 416 and in some cases 303 ss is more labor intensive to cut. What I dont know is the grade of SS or Steel that Krieger or any other barrel manufacturer uses as its not my area of specialty. We have a chart based on C1212 being 100% machinability the following alloys are:
416A (annealed) 75%
430A 66%
4130 72%
4140 66%
1045 57%
IMO the 2 most likely candidates for barrels are 430ss and 4140cm which are about the same machinability. I know that many of the Mil-Surp barrels were actually made from 1045.
Is it possible this is just a preference with no real obvious advantage to either?

[BoogieMan]

Forever, until you fired the first shot...Tungsten Carbide is very hard, but like many hard materials, the hardness comes at the expense of being brittle. Gun barrels have to have some toughness.

Modern carbide blends are quite shock resistant and very good at absorbing stress,impact,tensile etc.. Elasticity is low.
But my point was that hardness alone is not what makes a barrel accurate or long lived.

[Jimro]

I can tell you that with the exception of 416 and in some cases 303 ss is more labor intensive to cut. What I dont know is the grade of SS or Steel that Krieger or any other barrel manufacturer uses as its not my area of specialty.

Krieger just states that they order their steel custom from the mill.

The bulk of stainless barrels on the market are 416R, and they do quite well accuracy wise.

There are other stainless barrel options out there, including 410 and LW50 which have been marketed to the AR crowd for longer barrel life.

Jimro

[BoogieMan]

The bulk of stainless barrels on the market are 416R, and they do quite well accuracy wise.

There are other stainless barrel options out there, including 410 and LW50 which have been marketed to the AR crowd for longer barrel life.

416 is much easier to machine than chro-mo and that makes sense why they can offer a higher cost raw material at the same cost as the chro-mo. Cost is made up in the process.
410 is not easy to machine but it adds abrasion resistance above 416.
LW50 is likely a proprietary Loher Walther 50, probably just 410. In order to get custom alloys the minimum order is usually around 40k lbs. Thats a lot of barrels.

[BoogieMan]

The only plausible reason I have heard for one material over the other is resonant frequency is almost certainly different.

[mete]

416 is a high sulphur version of 410 --easier to machine .416R is made by Crucible and is a 416 with more precisely controlled amounts of sulphur. Military barrels at one time were 4140R ,again high sulphur for easier machining .
Krieger barrels were cryogenically treated [ today ? ] but never proved by me the metallurgist or many others.If it had been all the custom makers would be using them !
BTW 416R is good down to -40 F !

[Bart B.]

Yes, the resonant frequency differs; a tiny, insignificant amount. So does the heat expansion ratio. I'll calculate the resonant freq difference when I get access to my software. It's the third or fourth harmonic and barrel time that determines muzzle axis angle at bullet departure. But it's very repeatable for a given barrel and load; that's what matters. Later.......

It's the same as claiming higher velocity is better than slower for better accuracy. Stiffer barrels resonate at higher frequencies.

[Nathan]

Barrel whip, for one. A softer metal tends to flex more. Watch a slo-mo vid of an AR vs AK sometime.

I'm going to call this on to task. I don't know AK vs AR, but I know something about steel.

Given 2 barrels of identical dimensions, and dissimilar materials, the one with the higher modulus of elasticity will be stiffer. I think steel and stainless are the same... no, carbon steel is clearly better 29 vs 27.6....actually, this is pretty close. I think I used 30 for both all through school and got lots of A's!

Given a softer barrel and a harder barrel, the softer one will have a lower ultimate tensile strength.

What does this tell me about best barrel? Nothing! Talk to a barrel maker to get that info.

Fundamentally, barrel life is determined by crown damage and fracture toughness of the throat at elevated temperatures. Temp is the key variable and is driven by chamber design, rate of fire and velocity of the bullet.

Knowing those answers can allow your barrel maker or you to hone in on the right barrel material.....or you can match your gun....pretty is often the best way to decide!

[DR Owl Creek]

There's a really interesting article about barrels you should take a look at. It's primarily from the benchrest shooting perspective, but it covers everything from types of steels used, to contour, twist rates, types of rifling, grooves, fouling, fluting, etc. That article should answer any question you might have. Go to: http://www.6mmbr.com/barrelFAQ.html

Dave

[Chaz88]

Fundamentally, barrel life is determined by crown damage and fracture toughness of the throat

This is were I believe SS might have the edge over carbon steel. The nickel content, among other things, makes it more wear resistant than carbon. Might not be an exact analogy but if you have sharpened a carbon steel knife and a SS knife on the same stone it takes a lot longer to wear down good stainless to a sharp edge.