Barrel life Stainless vs Carbon steel

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Ok, so I was welding today and thought a piece I had done was cooled. I was wrong.

anyway its got me thinking about guns (don't take much to switch my train of thought to guns)

I was wondering about barrel life and erosion, Heat dissipation .....ect

can anyone compare the different types of barrel materials and how they react and how it effects their life

Stainless VS blued/carbon VS chrome lined VS what ever else is out their.
 
Chrome barrels are for corrosive ammo shooting surplus guns. A stainless barrel will shoot 35-40% more ammo through it before it deteriorates, and a stainless rifle needs less attention in a rainy-snowy environment.
 
Uh-huh - stainless is pretty tough ......

BUT Cold Hammer Forged is tougher and lasts longer.

You'll find CHF barrels in SANs, LWRC, some Colts, Daniel Defence, Fabarm, Ruger, SIG's made in Germany, etc. - lots of info on the 'net about this subject - pretty interesting.
(Even the old samurai swords were CHF - heated + bashed with a heavy hammer + quenched / stress relieved - so on, and so on ...)

Abby
 
The stainless used for barrel making is not your "standard" AISI/SAE 304/316 SS, which are of the austenitic type, but the ferritic martensitic type, very often equivalent or close to AISI/SAE 416, and it's a steel that takes quenching / heat treatment.
The carbon steel used for such barrels usually is equivalent or close to AISI/SAE 4140/4145.
If you check carefully, you will find that both steel types are Chrome alloys. The early alloyed barrels were often of the Nickel steel type.

Basically, what makes the SS a bit better than CS, is it's ability to reach better mirror-like surface finish. It's downfall is it's ability to handle cold environment, as it modifies it's physical properties. This issue seems to be much better handled today, but it's still an issue.

Check this out, it's some posts of the mid-90's from reputable people, in the early days of wide availability of SS barrels.

http://yarchive.net/gun/barrel/barrel_steel.html

Another great source is Fred Barker's article "Heat Checking In Rifle Bores" from 2005 Precision Shooting Magazine


As for thermal conductivity,

AISI 4140 = 42.7 W/m-K @ 100 Deg. C
AISI 416 = 24.9 W/m-K @ 100 Deg. C
 
Last edited:
Baribal said:
The stainless used for barrel making is not your "standard" AISI/SAE 304/316 SS, which are of the austenitic type, but the ferritic martensitic type, very often equivalent or close to AISI/SAE 416, and it's a steel that takes quenching / heat treatment.
The carbon steel used for such barrels usually is equivalent or close to AISI/SAE 4140/4145.
If you check carefully, you will find that both steel types are Chrome alloys. The early alloyed barrels were often of the Nickel steel type.

Basically, what makes the SS a bit better than CS, is it's ability to reach better mirror-like surface finish. It's downfall is it's ability to handle cold environment, as it modifies it's physical properties. This issue seems to be much better handled today, but it's still an issue.

Check this out, it's some posts of the mid-90's from reputable people, in the early days of wide availability of SS barrels.

http://yarchive.net/gun/barrel/barrel_steel.html

As for thermal conductivity,

AISI 4140 = 42.7 W/m-K @ 100 Deg. C
AISI 416 = 24.9 W/m-K @ 100 Deg. C
Click to expand...

So your saying that a stainless bbl could be prone to change in group size and POI in cold weather?
 
No. It's tensile strenght is modified by cold.
There are a lot of stories / pictures / testimonies about SS barrels blowing up under cold weather.
 
I read an article about the author using logic to determined that chrome moly should last longer and take throat erosion better due to higher temps or something like that. I don't know which last longer however I like the weather resistance .

I have burnt out a 270wsm in under 600 rounds in a ruger mkii Stainless , so I don't really know.

I machined stainless and chrome moly in an unhardened state both are very tough and require coolant and slow speeds.

I have melted a drill bit into a ball nose from lack of coolant in stainless .
 
In it's "Heat Checking In Rifle Bores" article, Fred Barker came with the conclusion that none is really better. They both handle heat checking (or micro-cracking) about the same. This is mainly due to the thermal shock that occurs when pressurized high temperature gases hit the throat and disapear in a very short time period. The fact that SS barrels can be a bit better polished gives it an very slight edge, but not more than that.
Cr-Mo (4140) steel dissipates heat 70% better than SS 416, but SS has 25% less thermal expansion, so both ends up equal.
 
It was explained to me that stainless will outlast carbon steel significantly due to the fact that throat erosion has an oxidization component to it, as well as the sandblast powder effect etc, etc.....if one can minimize any of the causes it will extend barrel life. Stainless steel reduces the oxidization component and extends barrel life by about 30-40% as has been mentioned. I must add the disclaimer that I am not a metallurgist and this is what I understood when it was being explained, which is not necessarily what was being said. It was much longer and detailed but this is the crux of it, as I understood it.
 
tylerjwitty said:
another thing to note is that I have had equal accuracy from both types of barrels.

Hunting accuracy that is . MOA or better
Click to expand...

I don't believe barrel material has anything what-so-ever to do with accuracy, Ron Smith made a barrel from rebar and used it on some kind of target rifle, to prove this exact point!! If the material is tough enough to resist the pressure, accuracy is more a product of how the barrel is made, than from what. I should mention this was heresay but from a source that knows him very well and has been 100% reliable in the past.
 
As far as hunting rifles go you would see no difference in accuracy between chrome moly blued barrels and stainless steel barrels as hunting cartridges are not accurate enough to determine true accuracy differences.

As far a serious Benchrest goes, there is no difference in accuracy between match grade quality barrels regardless of chrome moly or stainless. Why choose stainless - because it does last a bit longer and you never have to worry about moisture damage and you don't have to blue it. Of the many chrome moly used hunting rifles I clean and inspect, many have rust pits within the last 4 inches of barrel, some throughout the barrel... that never happens with stainless barrels. Chrome moly requires more care throughout it's life.
 
The stainless used for barrel making is not your "standard" AISI/SAE 304/316 SS, which are of the austenitic type, but the ferritic martensitic type, very often equivalent or close to AISI/SAE 416, and it's a steel that takes quenching / heat treatment.
The carbon steel used for such barrels usually is equivalent or close to AISI/SAE 4140/4145.
If you check carefully, you will find that both steel types are Chrome alloys. The early alloyed barrels were often of the Nickel steel type.

Basically, what makes the SS a bit better than CS, is it's ability to reach better mirror-like surface finish. It's downfall is it's ability to handle cold environment, as it modifies it's physical properties. This issue seems to be much better handled today, but it's still an issue.

Check this out, it's some posts of the mid-90's from reputable people, in the early days of wide availability of SS barrels.

http://yarchive.net/gun/barrel/barrel_steel.html

Another great source is Fred Barker's article "Heat Checking In Rifle Bores" from 2005 Precision Shooting Magazine


As for thermal conductivity,

AISI 4140 = 42.7 W/m-K @ 100 Deg. C
Click to expand...

Thanks .. and an interesting link worth reading. Personally I havent been enamored of stainless barrels .. but that is because I dont shoot well enough to appreciate the advantages in a target rifle ... and try not to stand around in the rain if I can avoid it when hunting ( I am a woose!! .. there .. I said it!)

Like a crow - I am attracted to SHINY blued metal . I like the fact that the protective covering (bluing) on my rifle barrel is so attractive .. and can be replaced if necessary ... always have since my first Red Ryder BB gun!. I particularly like the blued Steyr barrels cause the hammer swirls accentuate the shine!. Anyway it seems to me that the military have generally avoided SS for barrels even when a straight stainless would be cheaper than a hammer forged and chrome lined barrel. Also if stainless was significantly better at handling heat .. I think we would see more gpmg barrels constructed of the material .. as it is (AFAIK) most such barrels are 4140. I "believe" that even the 20mm M61 Vulcan barrels are 4140 (chrome lined) fwiw ... to be fair I understand that these barrels are essentially "Class C" disposable - but still I think the military may have concluded for a variety of reasons (erratic performance in extreme cold?) to stick with so called "carbon steel" vs "stainless steel" ( however one differentiates between the subtle difference between them)
 
SS barrels, when miror-like finished, need less cleaning as they show less asperities, this also results in less friction heat from the bullet passing through.

But for an average hunter, there is no difference excepted that the SS barrel will need less maintenance - but still need to be dried after being exposed to humidity, as ferritic SS rust (to a lesser degree than 4140, but still rusts).
 
SS barrels, when miror-like finished, need less cleaning as they show less asperities, this also results in less friction heat from the bullet passing through.
Click to expand...

Makes sense .. however somewhere (cant recall exactly where) pretty certain I read that one barrel maker of high repute commented that a barrel can be "too smooth" internally which prevented it from achieving optimum accuracy ... who knows... but the variety and choices are certainly great! Would add that I am not sure a mirror finish would reduce friction or not...
 
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