Why use a carbon wrapped barel?

[tacomHQ]

Tacomhq barrels:
Heat mirage is nearly non-existent.
The ability to shoot a wide range of bullets within the same vertical.
Given a correct bullet for the twist rate and a concentric load - I expect the barrel to shoot.
We demo huge bullet weight ranges within the same gun for that pointed purpose.
Much more forgiving for a ladder test. Quote "I shot a 11 grain ladder test- I would have used 8 of them normally they shot that good".
Recoil is reduced- it is the top first comment people make when they shoot our barrels. Reduce the harmonic whip- stay on target better.
It is a radiator. A purposely designed stiff radiator.
They are in the same weight category as current steel barrels used by F1 and PRS guys.
"Why aren't they used by the F1 guys" - absolutely fair question. Let's see what happens. F1 teams have shot our stuff. They bought barrels on the spot.
"Why do we demonstrate 70+grain bullet weight variations (300cal, 375cal...) nobody will ever shoot such a range": Diva. I do not consider a barrel design great if it can only shoot one bullet with one specific powder charge. The demonstration is to show the barrels ability to hold a vertical line with changing inputs. My thought is that in the field inputs change.
Again- Apologies given to this CF thread. It did branch into shooting avenues outside of hunting. I think part of it is

what your goal is: if its a all up 7lb 300WM CF all the way (I don't want to shoot it as I don't like being kicked by a mule plus I am not a tri-athlete getting up and down those mountains) or if your goal is a 12lb all up.... well I am prejudice towards our barrel.
The bottom line fact is this thread is about weight and 1-3rounds max.

 

[DJ Fergus]

Do I have any obligation? You're asking someone to invest countless hours to generate an incredibly complex algorithum (mathematical model) to satisfy your personal curiousity.

Research the Thermal Conductivity Coefficient for the carbon fiber wrap media the barrel manufacturer is using, and compare it to the Thermal Conductivity Coefficient for steel barrels. The generic, one-size-fits-all answer to your curiousity is, "The barrel material with the higher Thermal Conductivity Coefficient will transfer heat at the higher rate. Which is the same as saying, it will cool down (shed heat) at a faster rate.

Your problem will be, no carbon barrel manufacturer employee will provide the value for their CFW, unless that employee wants fired. Because that value will burst the perpetual propaganda bubble.

If you wanna spend your time and money satisfying a curiousity, I'd suggest purchasing equipment that will reliably measure the temperature of the bore in your CFW and a 100% steel barrel of identical size. Shoot the exact same cartridge and ammunition in each of the two identically shaped barrels, at the same rate of fire, under the same outdoor temperatures, at the same location and time, with no wind, and both barrels either in broad sunlight, or under shade. Place the temperature sensor in the bore immediately after firing a string of rounds down both barrels. The temperature sensor will need to be placed identically in both bores, and never be moved as the temperatures are being collected. It would be ideal if the temperature sensor wasn't in direct contact with the steel bore, but was held centered in the bore with an air gap circumferally surrounding the sensor. Monitor and record the bore temperatures versus time. Keep everything as apples to apples as possible, meaning control all temperature affecting influences. Measure and compare bore temperatures over time and voila, you will have demonstrated with empirical temperature data collected over time, which barrel cooled down quicker (transfered heat out from the bore at the faster rate).

It would be ideal to have two temperature sensors recording the rate of bore cool down in both barrels at the same time. And then perform a second test swapping the temperature sensing equipment between barrels and documenting the same result. In other words, strive for a well controlled test, in the effort to yield the most equally comparable and defendable temperature data.

So do you like carbon fiber barrels?

 

[tacomHQ]

My 338 barrel , 34" aol , shank 1.37 , 5" chamber , muzzle 0.800 , about 8.5 pounds

We calculate very precisely including cartridge volumes.
Action threads, brake, Chamber areas (OD and ID) threading.... Its a solid page of calculation. We also calculate per inch using those inputs.

 

[tacomHQ]

Do I have any obligation? You're asking someone to invest countless hours to generate an incredibly complex algorithum (mathematical model) to satisfy your personal curiousity.

Research the Thermal Conductivity Coefficient for the carbon fiber wrap media the barrel manufacturer is using, and compare it to the Thermal Conductivity Coefficient for steel barrels. The generic, one-size-fits-all answer to your curiousity is, "The barrel material with the higher Thermal Conductivity Coefficient will transfer heat at the higher rate. Which is the same as saying, it will cool down (shed heat) at a faster rate.

Your problem will be, no carbon barrel manufacturer employee will provide the value for their CFW, unless that employee wants fired. Because that value will burst the perpetual propaganda bubble.

If you wanna spend your time and money satisfying a curiousity, I'd suggest purchasing equipment that will reliably measure the temperature of the bore in your CFW and a 100% steel barrel of identical size. Shoot the exact same cartridge and ammunition in each of the two identically shaped barrels, at the same rate of fire, under the same outdoor temperatures, at the same location and time, with no wind, and both barrels either in broad sunlight, or under shade. Place the temperature sensor in the bore immediately after firing a string of rounds down both barrels. The temperature sensor will need to be placed identically in both bores, and never be moved as the temperatures are being collected. It would be ideal if the temperature sensor wasn't in direct contact with the steel bore, but was held centered in the bore with an air gap circumferally surrounding the sensor. Monitor and record the bore temperatures versus time. Keep everything as apples to apples as possible, meaning control all temperature affecting influences. Measure and compare bore temperatures over time and voila, you will have demonstrated with empirical temperature data collected over time, which barrel cooled down quicker (transfered heat out from the bore at the faster rate).

It would be ideal to have two temperature sensors recording the rate of bore cool down in both barrels at the same time. And then perform a second test swapping the temperature sensing equipment between barrels and documenting the same result. In other words, strive for a well controlled test, in the effort to yield the most equally comparable and defendable temperature data.

Machine a piece of Graphite 2+" long x bore -.010"- light sand blast on the body . Seat it into a piece of brass. This black body is extremely reliable for IR gun use. IR guns are very picky for what the surface reflection/specular finish is. Fire your string chamber the Graphite round weight blank time and pull it with immediate measurements.
Without cringing- a piece of aluminum- sand blast- wrap with tape/shrink wrap every 10" or so to protect barrel and center it without direct contact- insert and heat soak it as a base value and trend guide. A long enough rod will allow you to push the rod into the action from the chamber getting a read- or any value along its length. Crude but a reference.

 

[UniqueUserName]

Burden of what? I am asking the question based on no experience in thermal modeling. You said a lot in your post and explain that you understand this area much more than me, but want to make this an argument rather than just putting some simple numbers to the volumes I've given. If you don't know how to run the numbers, fine, neither do I, but I will learn

The burden of building the model that you require.

I understand many of the factors and the process of heat transfer, but I'm neither capable of building an accurate predictive model or willing to attempt to do so in order to satisfy someone else's skepticism. I also haven't heard anyone else make a credible claim to be both capable and willing to do so. That leaves you in the position of doing it yourself or finding/hiring someone else capable and willing to do it for you.

 

[Mram10us]

Do I have any obligation? You're asking someone to invest countless hours to generate an incredibly complex algorithum (mathematical model) to satisfy your personal curiousity.

Research the Thermal Conductivity Coefficient for the carbon fiber wrap media the barrel manufacturer is using, and compare it to the Thermal Conductivity Coefficient for steel barrels. The generic, one-size-fits-all answer to your curiousity is, "The barrel material with the higher Thermal Conductivity Coefficient will transfer heat at the higher rate. Which is the same as saying, it will cool down (shed heat) at a faster rate.

Your problem will be, no carbon barrel manufacturer employee will provide the value for their CFW, unless that employee wants fired. Because that value will burst the perpetual propaganda bubble.

If you wanna spend your time and money satisfying a curiousity, I'd suggest purchasing equipment that will reliably measure the temperature of the bore in your CFW and a 100% steel barrel of identical size. Shoot the exact same cartridge and ammunition in each of the two identically shaped barrels, at the same rate of fire, under the same outdoor temperatures, at the same location and time, with no wind, and both barrels either in broad sunlight, or under shade. Place the temperature sensor in the bore immediately after firing a string of rounds down both barrels. The temperature sensor will need to be placed identically in both bores, and never be moved as the temperatures are being collected. It would be ideal if the temperature sensor wasn't in direct contact with the steel bore, but was held centered in the bore with an air gap circumferally surrounding the sensor. Monitor and record the bore temperatures versus time. Keep everything as apples to apples as possible, meaning control all temperature affecting influences. Measure and compare bore temperatures over time and voila, you will have demonstrated with empirical temperature data collected over time, which barrel cooled down quicker (transfered heat out from the bore at the faster rate).

It would be ideal to have two temperature sensors recording the rate of bore cool down in both barrels at the same time. And then perform a second test swapping the temperature sensing equipment between barrels and documenting the same result. In other words, strive for a well controlled test, in the effort to yield the most equally comparable and defendable temperature data.

I am not asking for anything except numbers to back why you think CF barrels do not cool as fast. What numbers are you using for Therm Cond? They are all over the place depending on what epoxy is used. You want me to explain why I think they would cool faster, when I have very little experience with regard to thermal formulas, but won't do it yourself when you act as though you have a handle on this. Not sure why some have turned this into an argument rather than just showing in a basic form, why CF does or does not cool faster. You are writing a lot, but basic numbers would be helpful.
Example: there was a study done by the U of Nebraska. They listed thermal conductivity of CF with specific resins around 5-7. When comparing to Stainless steel(13), and taking into account half the volume of steel between the two barrel types, that puts them close.

 

[Pdvdh]

Yes. That's why I just purchased two more.

Primary reasons? 1) I don't shoot my barrels at rates of fire that cause me concerns with respect to overheating the bores. The whole topic of cooling rates of the CFW has no negative consequences for my use of my CFW barrel. 2) They're proving accurate enough for my hunting needs. 3) I highly value the lighter weight and better rifle balance with the carbon fiber wrapped barrels attached to my actions. 4) I backpack hunt in the hills and mountains of Alaska, almost solely. Which means I typically carry my hunting rifles 99.9% of the time and shoot them less than 0.1% of the time during my hunting. I'm getting older. The same mountains I hiked the year before become more fatiguing the next year. It's as if the slopes increase year by year. So I'm willing to pay more for the CFW barrel if they extend my time afield, provided they meet my accuracy requirements.

I suppose the biggest single reason is weight reduction. When I find myself cussing the carry weight of my rifle, it's time to act. In my case, reduce all aspects of my rifle builds, and CFW barrels is one component that gets swapped into use. Having said that, I don't want or like an ultralight rifle for long range hunting. Out to 5-600yds, they're fine if they shoot. I find the ultralights overly difficult to pilot for the longer range shots I'm preping for. Guess I lack the nerves of steel to pilot the ultralights at long range.

 

[Pdvdh]

They listed thermal conductivity of CF with specific resins around 5-7. When comparing to Stainless steel (13), and taking into account half the volume of steel between the two barrel types, that puts them close.

And there you have it. They're stating the CF media with resins will transfer heat at ~1/2 the rate of SS. The Christensen engineer provided a TC value for their CF media at a value that would cool more on the order of 1/3 to 1/4 that rate of barrel steel.

If that's close enough for you, that's all that matters. No?

 

[DJ Fergus]

This is a little off topic, I had a carbon fiber gear shifter knob back in the 90s. It was supposed to reduce my shift time and some claimed the reduction in the overall total vehicle weight also improve track time. I really don't know about all of that but it looked really cool. All of my friends liked it. I thought it was a good investment at the time.




Please forgive me, I just posted this in good humor. I think we all need a laugh from time to time.

 

[Mram10us]

And there you have it. They're stating the CF media with resins will transfer heat at ~1/2 the rate of SS. The Christensen engineer provided a TC value for their CF media at a value that would cool more on the order of 1/3 to 1/4 that rate of barrel steel.

If that's close enough for you, that's all that matters. No?

No The rate is based on the amount of steel, which I computed earlier as about half (10in^3 v 20in^3). That is why I am wondering why so called engineers are stating opinions with no numbers. I have known and still know many engineers because of my profession and those dudes can't tell me where to go to lunch without giving numbers Again, this shouldn't be a battle, just a simple pulling together of variables with some 10lb head running them thru some basic formulas. If fusion360 does it, I will try it out. My CAD and CAM skills are basic at best.

 

[UniqueUserName]

I am not asking for anything except numbers to back why you think CF barrels do not cool as fast. What numbers are you using for Therm Cond? They are all over the place depending on what epoxy is used. You want me to explain why I think they would cool faster, when I have very little experience with regard to thermal formulas, but won't do it yourself when you act as though you have a handle on this. Not sure why some have turned this into an argument rather than just showing in a basic form, why CF does or does not cool faster. You are writing a lot, but basic numbers would be helpful.
Example: there was a study done by the U of Nebraska. They listed thermal conductivity of CF with specific resins around 5-7. When comparing to Stainless steel(13), and taking into account half the volume of steel between the two barrel types, that puts them close.

You have your answer in the very numbers that you cited regarding the relative thermal conductivity of the materials. Adding greater thickness or mass of CF does not enhance its thermal transfer rate, it further degrades it, relative to steel. Adding more insulation to an object does not cause it to shed heat faster (don't confuse thermal transfer rate with thermal capacity). It causes that object, in this case the liner, to retain heat longer. Nevermind the potential/likelihood of imperfect contact in the interface between the steel liner and the CF wrap.

To be clear: I'm not anti-CF. I have a CF wrapped barrel on a hunting rifle. I like it both for weight savings and aesthetics. Any decrease in cooling performance is a non-factor in my application.

 

[Mram10us]

You have your answer in the very numbers that you cited regarding the relative thermal conductivity of the materials. Adding greater volume or mass of CF does not enhance its thermal transfer rate, it further degrades it, relative to steel. Adding more insulation to an object does not cause it to shed heat faster. It causes that object, in this case the liner, to retain heat longer.

With half the volume of steel? So a barrel liner as thin as a piece of tin foil v a 1.250 straight barrel would cool the same if wrapped in cf? See my confusion? Maybe CFE is only a very small part because specific heat takes volume into account, which makes sense for our debate.

 

[Pdvdh]

No The rate is based on the amount of steel, which I computed earlier as about half (10in^3 v 20in^3). That is why I am wondering why so called engineers are stating opinions with no numbers.

OK. If you say so.

I'm a so-called engineer. But I owe you nothing. I don't wanna state my opinion with numbers you desire. Never gonna do it without engineering pay. Anyhow, I'm just a a so-called engineer. What could I offer of any real value?

The most pertinent material property (coefficient) has been identified for your use and understanding. Still not sufficient for your personal needs.

Maybe research locating, contacting, and badgering one of your REALLY GOOD "so-called" heat transfer engineer friends.

 

[UniqueUserName]

With half the volume of steel? So a barrel liner as thin as a piece of tin foil v a 1.250 straight barrel would cool the same if wrapped in cf? See my confusion? Maybe CFE is only a very small part because specific heat takes volume into account, which makes sense for our debate.

I do see your confusion. I've tried to help you with it. I brought up the topic of thermal capacity many, many posts ago. Thermal capacity is a property of both the material itself and the mass of that material. Did you see mass represented as a property of thermal conductivity?

Full disclosure, less you mischaracterize anything I have said about myself. I am not a "so called" engineer and I have not represented myself as an "expert". I have given my relevant certification and represented my opinions based on my knowledge and experience in the field. I am not capable of producing the predictive model that you demand, though I believe I have a grasp of the key factors and variables. I believe that I am capable of creating a valid test for a specific set of control variables, but in all candor, I have no desire to do so in order to satisfy your skepticism. If you want proof by predictive model or testing, you're going to need to invest your own time, material and knowledge to do that.