Fluted Bartlein vs Proof Research sendero contours

[Pdvdh]

From multiple sources I've listed and looked at the highest conduction I've seen for carbon is 24 and the lowest I've been able to find for steel is 24.9 in most cases it looks like carbon has half the conduction or less.

Yup. You're well on your way. I thinks you have a science background. At the minimum, an avid interest.

My schooling was in engineering. I got a butt load of heat transfer and thermodynamics coursework.

It all comes down to thermal conductivity. I think I'll move over now and let you lead!

Before I overload and overheat the circuitry.

 

[Browning300]

Haha just wrap it in a little carbon fiber and sprinkle a good helping of magic dust and you'll have no more trouble with that nasty little heat gremlin sir I can guarantee it

 

[RockyMtnMT]

It starts out frozen doesn't it? What else do you need to know?

Steve

 

[Deleted member 103481]

From anyone that has used a carbon wrapped barrel what have your observations been on Point of impact shift?

Other than barrel life and throat erosion this is really what we care about when considering a barrel heating up correct? Tossing whether the barrel is hotter out the window since we have pretty much exhausted that on paper, this it seems is what is left.

It seems unlikely shift would be less than a steel barrel of equal contour even if carbon greatly increases rigidity. However, would the rigidity increase of a carbon barrel in an MTU profile/proof sendero (3 pounds?) play into a reduced impact shift over consistent firing compared to a steel barrel at 3 pounds (approx #2 depending on who made it)?

 

[Elk Hunter 338]

That's not saying a whole lot as to the apparent decibel reduction on your rifle!

Is it better than the rifle without either a brake OR a 'standard efficiency' suppressor?

its about like having a non broke 26" 22-250 i would say. I measure all cans suppression and accuracy to my thunderbeast cans! they are pretty much the **** as far as i can tell for accuracy, longevity, DB ratings and of course strength! I'm a firm believer in their core design and metallurgy!! i am going to run my TBAC on my new short barreled 22" 338 RUM should be quiet and still able to swing in the timer or alders

 

[CA48]

From anyone that has used a carbon wrapped barrel what have your observations been on Point of impact shift?

Other than barrel life and throat erosion this is really what we care about when considering a barrel heating up correct? Tossing whether the barrel is hotter out the window since we have pretty much exhausted that on paper, this it seems is what is left.

It seems unlikely shift would be less than a steel barrel of equal contour even if carbon greatly increases rigidity. However, would the rigidity increase of a carbon barrel in an MTU profile/proof sendero (3 pounds?) play into a reduced impact shift over consistent firing compared to a steel barrel at 3 pounds (approx #2 depending on who made it)?

My 6.5x47 with a 24" MTU contour has POI shift until about the 3-4th round fired from a cold bore then it starts to settle. My 6.5SS with a 26" proof contour does not have a poi shift as it's warming up from a cold bore. A buddy of mine one day at the range had 6 or 7 guys line up with their proof rifles of various chamberings and shoot 10shots (don't remember the yardage but probably 1-200 yards. Then he had them grab their steel barreled rifles and repeat the process. The proof barreled rifles did not have poi shift from a cold bore.

 

[Deleted member 103481]

My 6.5x47 with a 24" MTU contour has POI shift until about the 3-4th round fired from a cold bore then it starts to settle. My 6.5SS with a 26" proof contour does not have a poi shift as it's warming up from a cold bore. A buddy of mine one day at the range had 6 or 7 guys line up with their proof rifles of various chamberings and shoot 10shots (don't remember the yardage but probably 1-200 yards. Then he had them grab their steel barreled rifles and repeat the process. The proof barreled rifles did not have poi shift from a cold bore.

Extremely interesting and promising experience. Thank you!

 

[FURMAN]

Here are some facts for those seriously interested instead of the wild speculation being spouted in this thread. The thermal conductivity and specific heat capacity of the two barrel materials CAN NOT be compared like some individuals in this thread are trying to do because one of the materials is homogenous and the other is not. This is from the Christensen Arms engineer. If you are really interested you can find this information repeated from the aerospace engineers.

Hello Ryan,


The thermal conductivity of carbon fiber material, generally is not rated as it varies between many factors. Several key factors that play into the thermal conductivity, or diffusivity, are: mass, volume, ply orientation, resin saturation, and the primary material components as well. There were test performed years ago, before my time; however, they have been archived and it would take some digging to get them out. I can easily supply you the engineering behind the claims, especially at a face value, when considering only the thermal conductivity, density, and specific heat, see below:


Thermal Diffusivity (α): The ability of a material to conduct thermal energy relative to its ability to store thermal energy. Materials with a large thermal diffusivity will respond quickly to changes in their thermal environment, while materials of a small thermal diffusivity will respond more sluggishly, taking longer to reach a new equilibrium condition.

α = k/ ρcp


Example: Carbon Vs. Steel

Carbon Steel: k = 60.5 w/m*k, ρ = 7854 kg/m3, cp = 434 J/kg*k

α = (60.5 w/m*k)/ ((7854 kg/m3)*( 434 J/kg*k)

α = 1.80 E-5 m2/s



Carbon Fiber (25% epoxy):

Parallel to fibers: k = 11.1 w/m*k, ρ = 1400 kg/m3, cp = 0.982 J/kg*k

α = (11.1 w/m*k)/ ((1400 kg/m3)*(0.982 J/kg*k)

α = 8.07 E-3 m2/s

Perpendicular to fibers: k = 0.87 w/m*k, ρ = 1400 kg/m3, cp = 0.942 J/kg*k

α = (0.87 w/m*k)/ ((1400 kg/m3)*(0.942 J/kg*k)

α = 6.60 E-4 m2/s

This means that carbon fiber epoxy parallel to fibers has an approximate thermal diffusivity of 450 times greater than carbon steel and perpendicular is approximately 37 times greater.


The fact that the user does not feel the barrel getting hot is due to the volume of the barrel and rapid heat dissipation through the length of the barrel, not just the chamber or muzzle end. We run a larger contour than that of standard barrel contours, unless ordered as a heavy barrel contour. A proper test would be to use the same contour steel barrel and compare against a carbon wrapped barrel of the same finished contour. This test can be accelerated when using a semi-auto rifle platform.


I know this isn't the graphs and charts that you were looking for, but this is the science behind the claim. I hope this helps. If we conduct another test in the future I will be sure to get with Eric and help with information/education.


Thanks,


Casey Hill

Design Engineer

Christensen Arms

[email protected]

(435)528-7999 ext. 427

 

[FURMAN]

As some have stated I do not even know why anyone cares about heat dissipation in a hunting rifle but Bryan Litz has some great POI shift data in his books.

 

[Smokinghole]

I still want a carbon barrel. Even for the light casual target shooting I do. I'm not putting rounds down like competition does. To me they're lighter compared to a similar length and diameter steel barrel, basically good enough for me.

 

[5RWill]

Currently looking for a 24" proof .284 sendero light. Gun currently weighs 12.5-13lbs with an 18" Bartlein RV, can, and bipod. I'm hoping to stay around that weight or drop some. Certainly can't do that with 24" RV contour or #4 or probably even a #3B. Don't want to go thinner than a 3B, so it fits that niche...just need to find one at a decent price.

 

[lancetkenyon]

I have 2 lighter weight HUNTING rifles that I am currently using for deer/elk.

1st: 7RM built by Phoenix Custom Rifles
R700 LA BDL trued
26" Bartlein #3B fluted 1:8.5" w. APA Micro Bast brake
Timney CE trigger
Manners EH-2
Seekins 20MOA alloy Picatinny rail
Seekins 34mm low alloy rings
S&B PMII 3-20x50 w. Vortex Lo Pro level
10lbs 9oz w. cheek pad and sling
180 Hybrid @ 2996fps
Shoots .1-.2 out to 1000+. Sub 3" @ 1000. 5" @ 1542.


I have not noticed a POI shift from cold bore to 3 consecutive shots immediately following with the Bartlein.
Cold Bore shot:


3 shot group immediately following CBS above.


2nd: .280AI built by AxisWorks
R700 LA BDL trued
26" Proof Research Sendero Light 1:9" w. Hawkins 3 port
Shilen Match trigger
Manners EH-1
Seekins 20MOA Picatinny rail
Seekins 30mm low alloy rings
Premier Heritage Light Tactical 3-15x50 w. Flatline Ops level
Carbon Fiber tactical knob
Alloy bolt shroud
Fluted bolt body
8lbs 15oz w. cheek pad & sling
175 Berger Elite Hunter @ 2975fps (hot load)
Shoots .2-.3s out to 1000. Sub 3" @ 921. 6" @ 1565.



3 shot group during final sight in (CBS+2 more)


Moved up and right, put these 3 down immediately following first 3 shots. (don't mind the .204" hole)

I am not worried about barrel heating up, as if I need to take more than 2 or 3 shots with a hunting rifle, there is something wrong.

As for weight, I think the Proof might save 6-10oz over a lighter contoured (#3 to #4) steel barrel. I lost almost a full pound by going 26" Proof over 28" Shilen #4. Fluting saves 2-10 oz depending on barrel contour, number of flutes, depth of flutes, and straight or helical fluting. My Rock Creek 28" Rem Varmint contour saved 9.5oz by deep helical fluting. Yet my 26" Bartlein #3B only saved about 4oz by helical fluting. Not sure the difference in weight between my 26" Bartlein #3B w. straight flutes over a non-fluted. But probably not more than 2-3oz.

Lot of other places to save weight too. Some major, some minor.
Stock materials & features, scope, base & rings vs. lightweight rings, titanium actions vs. steel, long vs. short actions, alloy bolt shroud/fluting/knob/skeletonizing bolts/handles, barrel length, muzzle brakes, slings, etc.

 

[5RWill]

I have a spiral fluted 3B on dad's rifle and thought about going that route on my TL3/EH1 seems the sendero lite is indeed lighter at 26". A #4 from Bartlein at least is a pretty large barrel. It's right there with an RV contour. I probably need to move to a lighter scope but that wont happen for some time. The SN-3 is 35oz i think.

When you consider fluting it really isn't all that much difference. 500-525$ for a fluted bartlein, 730$ for a proof.

 

[lancetkenyon]

Bartlein #3B spiral fluted ($350+ 125 for fluting)




Rock Creek "Rem Varmint" spiral fluted ($400+$120 for fluting)


Bartlein #3B straight fluted ($450 from Grizzly Supply)


Proof "Sendero Light" (I got a screaming deal, but normally $750-850?)