Fluted Bartlein vs Proof Research sendero contours

[Deleted member 103481]

Scratch that last statement accurate or alpha will be fine and give you over 2.93

Werent you saying you fit 2.95 in an accurate mag and 2.97 in an alpha in your earlier post?

 

[5RWill]

Werent you saying you fit 2.95 in an accurate mag and 2.97 in an alpha in your earlier post?

Yeah i edited my last post because i had misread. 2.970 for the alpha for sure and despite the Accurate saying 2.950 our 6.5 SAUM rounds at 2.960ish fit.

 

[bigngreen]

You mean the manufacturer misrepresented their product's decibel reduction? From their website, you're supposed to be able to shoot that one in the house, next to the infant's crib.
"Hands down the quietest 375 Cheytac suppressor... ...we guarantee it."

That must only be true for the 375 Cheytac. OR, maybe it's not true for any cartridge.

We've ran them up to 338 Norma and we're impressed with them as a total package over the much heavier cans that we swapped them out with.
Being rated for a chambering means that it can handle it at a certain capacity and exit pressure nothing more!!
Super nice for timber hunting with 300's and keeping the length and ballance shootable in a regular hunting situation.

 

[Deleted member 103481]

Yeah i edited my last post because i had misread. 2.970 for the alpha for sure and despite the Accurate saying 2.950 our 6.5 SAUM rounds at 2.960ish fit.

Good deal, thanks for your help!

 

[Elk Hunter 338]

We've ran them up to 338 Norma and we're impressed with them as a total package over the much heavier cans that we swapped them out with.
Being rated for a chambering means that it can handle it at a certain capacity and exit pressure nothing more!!
Super nice for timber hunting with 300's and keeping the length and ballance shootable in a regular hunting situation.

yes i understand the rating that it can handle pressure wise!!! and yes its definitely light and reasonably short but just wasn't impressed with the amount of crack it let off!! but better than a huge brake i guess

 

[Pdvdh]

I haven't read the whole argument about this but here's this for a thought. Less metal means less mass. The entire liner would get hot faster than a barrel of the same size as the wrap because of the heat transfer rate. Smaller contour steel barrel will lead to faster heat up per shot fired than a larger contour steel because of less steel mass to absorb heat (same BTU heat generated in bore but there's less steel mass to distribute that heat into), not because of heat transfer rate. Not because of heat transfer rate, unless I misunderstand your analogy. The thermal conductivity of steel is the same, no matter the contour of the barrel, so the heat transfer rate in steel is not changed by barrel contour. Due to the decreased mass the liner sheds the heat faster because less metal got hot and therefore there are less BTUs to shed. BTUs as heat generated in the bore are the same no matter a steel barrel, a CF barrel, and no matter the thickness (OD) of the barrel. So the heat sink into the steel bore is roughly the same, provided the same caliber, cartridge, load, and length barrel. The liner of a CF wrapped barrel will only shed heat more efficiently if the carbon fiber is more thermally conductive than steel, given the CF and steel barrels are of equal contour (same OD along the length of the barrel).

Granted I do tend to think the carbon would prevent the barrel from shedding heat but if it is effective at heat transfer at all, it might lose heat at a faster rate than a sendero profile of all SS or chromoly. A CF wrapped barrel of equal outer profile (OD) to a 100% steel barrel will only cool down at a higher rate if the thermal conductivity of the CF is higher than the thermal conductivity of steel. Even then it would still take a while to cool down, because the temperature differential between the exterior surface of the barrel and the ambient air temperature is also involved in the rate of heat transfer. The higher the exterior surface of the barrel, the greater the rate of heat transfer to the lower temperature ambient air.

Lothar Walther used to have a aluminum sleeved barrel for center fire cartridges on their US website. It appears to be gone though. It used their LW50 SS as the liner and, what I assume, is a heat/cryo assisted press fit fluted aluminum sleeve. The thermal conductivity of aluminum is about 3 times greater than the thermal conductivity of steel. Bingo! The steel exterior sleeve would help transfer heat from the bore to the outer surface of the barrel faster, where the higher temperature of the outer barrel surface would result in a greater rate of heat transfer from the barrel to the surrounding ambient air. There is also Drake Associates that makes a Ti sleeved barrel. I haven't looked up the thermal conductivity of titanium. If it's greater than steel, then if used as an exterior sleeve, it would result in the faster transfer of heat from the bore to the exterior surface of the barrel, and just like the aluminum, a faster rate of hot barrel cool-down. Only in .308 bore though.

You'll have to expand your post above to read my response. Please excuse the bold font. I'm not screaming or yelling as I type, and not trying to respond in a loud-mouthed manner. Just did that so that my responses to the thoughts you've expressed in your post can be easily differentiated from one another.

In the very first bolded sentence of my response within your post above, I understood you to be comparing lighter versus heavier contour barrels consisting of 100% steel. If that's not what you meant, then my response would, of course, not be appropriate to the point you were making.

See how it all comes back to the thermal conductivity of the CF wrap? If they'd only provide that value to us, it would be so simple to cut to the chase.

If the CF wrapped barrel transfers heat from the bore to the exterior surface of the CF barrel at a higher rate than steel, then the exterior surface will heat faster and become warmer/hotter quicker than a 100% steel barrel of the same contour. A barrel that transfers heat faster from the bore to the exterior surface will result in the exterior of the barrel getting hotter faster. And a barrel with the higher exterior surface temperature will transfer heat to the surrounding ambient air at a higher rate - because of the higher temperature differential between the barrel and the ambient air. This is why our houses in northern climates cool down faster in colder winter temperatures than in warmer ambient air temperatures. Or in reverse, why houses in southern climates heat up faster when the outdoor ambient air is scorching hot. The rate of heat transfer increases, all else being equal, the greater the temperature difference between the two items/bodies/media involved in the conductive heat exchange.

So back to the questions I posed earlier. Why do the CF barrel manufacturers keep the whole subject so shrouded in mystery? Simply provide the thermal conductivity rating of the CF used to wrap your steel barrel cores. There was some loud-mouthed intention there. I suspect the why is because with that information, the whole "barrels remain cold as ice" advertising campaign goes Poof! No more pixie dust! No more mystery!

As I stated earlier, the best heat transfer related trait of a CF wrapped barrel is you'll be less apt to suffer burn blisters from extended high rates of fire. Because the CF wrap is such a good insulator. I'd like to think self-respecting CF barrel manufacturers would step into the fray. Because I'm beating them like a drum! Respond and make me eat crow. Please respond. Open invitation... Yet nothing but silence...

Where's myth busters when ya need them? Wouldn't fly on that show. If it doesn't explode, it didn't air on the myth busters television show...

 

[Pdvdh]

...better than a huge brake I guess

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?

 

[Smokinghole]

You'll have to expand your post above to read my response. Please excuse the bold font. I'm not screaming or yelling as I type, and not trying to respond in a loud-mouthed manner. Just did that so that my responses to the thoughts you've expressed in your post can be easily differentiated from one another.

In the very first bolded sentence of my response within your post above, I understood you to be comparing lighter versus heavier contour barrels consisting of 100% steel. If that's not what you meant, then my response would, of course, not be appropriate to the point you were making.

See how it all comes back to the thermal conductivity of the CF wrap? If they'd only provide that value to us, it would be so simple to cut to the chase.

If the CF wrapped barrel transfers heat from the bore to the exterior surface of the CF barrel at a higher rate than steel, then the exterior surface will heat faster and become warmer/hotter quicker than a 100% steel barrel of the same contour. A barrel that transfers heat faster from the bore to the exterior surface will result in the exterior of the barrel getting hotter faster. And a barrel with the higher exterior surface temperature will transfer heat to the surrounding ambient air at a higher rate - because of the higher temperature differential between the barrel and the ambient air. This is why our houses in northern climates cool down faster in colder winter temperatures than in warmer ambient air temperatures. Or in reverse, why houses in southern climates heat up faster when the outdoor ambient air is scorching hot. The rate of heat transfer increases, all else being equal, the greater the temperature difference between the two items/bodies/media involved in the conductive heat exchange.

So back to the questions I posed earlier. Why do the CF barrel manufacturers keep the whole subject so shrouded in mystery? Simply provide the thermal conductivity rating of the CF used to wrap your steel barrel cores. There was some loud-mouthed intention there. I suspect the why is because with that information, the whole "barrels remain cold as ice" advertising campaign goes Poof! No more pixie dust! No more mystery!

As I stated earlier, the best heat transfer related trait of a CF wrapped barrel is you'll be less apt to suffer burn blisters from extended high rates of fire. Because the CF wrap is such a good insulator. I'd like to think self-respecting CF barrel manufacturers would step into the fray. Because I'm beating them like a drum! Respond and make me eat crow. Please respond. Open invitation... Yet nothing but silence...

Where's myth busters when ya need them? Wouldn't fly on that show. If it doesn't explode, it didn't air on the myth busters television show...

If I had the money our resources I'd be down with testing and installing thermocouples on the barrels to measure heat.

Just thinking out loud mostly. Not making an argument either way, I own steel barrels. A barrel will only get so hot. You seem to know thermodynamics, or at least like to refute manufacturer claims. Would the lower mass of steel be advantageous? After all, boiling water will reach +/- 212°F at sea level, a smaller pot cools faster despite having been at the same temp. I accept that the carbon wrap is an insulator unless there is some sort of mix of carbon fiber mat and resin that actually conducts heat.

 

[Pdvdh]

You seem to know thermodynamics, Enough, but understand this isn't rocket science within the field of conductive heat transfer. This is really pretty basic. or at least like to refute manufacturer claims Maybe. Hadn't really dwelled on that thought/concept. Some members may benefit. They might like to know what they are, and aren't getting. I'm glad CF barrels are available, so I don't have a problem with CF barrels. Just the false advertising. Would the lower mass of steel be advantageous? No, not when it's covered with insulating CF wrap. It will heat up a little faster than a non-insulated steel barrel, it will reach a higher internal temperature compared to a non-insulated steel barrel, and then cool down more slowly. All the opposite of what I prefer. So in addition to being light barrels for their size, they'll also retain heat longer - doubling as hand warmers. After all, boiling water will reach +/- 212°F at sea level, a smaller pot cools faster despite having been at the same temp. Smaller pot of water will both heat and cool over a shorter period of time due to the lesser mass of water and the lesser energy required to heat that smaller mass. Cools over a shorter period of time because less mass of water doesn't store as much heat energy. Same with smaller and larger steel barrels. Small ones heat up faster during fire, which can have a negative affect on accuracy. Small ones will actually transfer heat to the ambient air at a higher rate, because they will have reached a higher external temperature than a larger steel barrel. Once the external temperature of the smaller steel barrel cools to the same (lower) temperature of a heavier steel barrel during cool down, the rate of heat loss would be about identical for that instant of time. However, as soon as the small barrel temp has cooled to a temp less than the heavy barrel, then the heavy barrel would be transferring heat to the air at a higher rate because it's now at the higher temp. I accept that the carbon wrap is an insulator unless there is some sort of mix of carbon fiber mat and resin that actually conducts heat. I've read that carbon materials can be manufactured with really high thermal conductance, but that it's very costly (prohibitively so) for common plain-Jane use. If the CF rifle barrel manufacturers are using high heat conducting carbon fiber wrap that exceeds the thermal conductance of barrel steel, then their claims of running cooler could have merit. But also, why wouldn't they provide those specs. Anyhow, at best, it's not dry ice. The bore is still gonna get hot.
Until the CF barrel manufacturers test, establish, and provide the thermal conductance rating of their CF wrap, the best the average CF barrel owner can do to test the heat transfer properties of their carbon wrap (relatively better or worse than steel) is measure or feel the temperature of their CF barrel compared to their steel barrels.

 

[Browning300]

DESCRIPTION
Type 416 stainless steel is a martensitic, free machining grade that can be hardened by heat treating to increase strength and hardness. The alloy exhibits machinability that is better than austenitic grades but sacrifices corrosion resistance.

CHEMISTRY TYPICAL
Carbon: 0.15 max
Phosphorus: 0.060 max
Silicon: 1.00 max
Manganese: 1.25 max
Sulfur: 0.150 min
Chromium: 12.00-14.00

PHYSICAL PROPERTIES
Density: 0.282 lbs/in3 7 .80 g/cm3

Electrical Resistivity: ohm-cir-mil/ft:
At 70 °F (21 °C): 343.0

Specific Heat: BTU/lb-°F (J/g-°C):
32 - 212 °F (0 - 100 °C): 0.110 (0.460)

Thermal Conductivity: BTU-in//hr-ft2-°F (W/m•K)
At 200 °F (94 °C): 172.8 (24.9)
At 1000 °F (538 °C): 198 (28.5)

Mean Coefficient of Thermal Expansion: µin/in-°F (µm/m-°C)
32 - 212 °F (0 - 100 °C): 5.50 (9.90)
32 - 600 °F (0 - 316 °C): 5.60 (10.1)
32 - 1200 °F (0 - 649 °C): 6.5 (11.7)

Modulus of Elasticity: KSI (MPa)
29.0 x 103 (200 x 103) in tension

Melting Range: 2700 - 2790 °F (1488 - 1530 °C)

So here it seems that the thermal conductivity w/m-k is 24.9

8- Thermal Conductivity of Carbon Fiber
See my article on Heat Conductivity of Carbon Based materials including carbon fibre, nanotubes and graphene.

Thermal conductivity is the quantity of heat transmitted through a unit thickness, in a direction normal to a surface of unit area, because of a unit temperature gradient, under steady conditions. In other words it's a measure of how easily heat flows through a material.

There are a number of systems of measures depending on metric or imperial units.

1 W/(m.K) = 1 W/(m.oC) = 0.85984 kcal/(hr.m.oC) = 0.5779 Btu/(ft.hr.oF)

This table is only for comparison. The units are W/(m.K)

Air .024
Aluminium 250
Concrete .4 - .7
Carbon Steel 54
Mineral Wool insulation .04
Plywood .13
Quartz 3
Pyrex Glass 1
Pine .12
Carbon Fiber Reinforced Epoxy 24
Because there are many variations on the theme of carbon fiber it is not possible to pinpoint exactly the thermal conductivity. Special types of Carbon Fiber have been specifically designed for high or low thermal conductivity. There are also efforts to Enhance this feature.

Here it seems that it's w/m-k 54 for steel and carbon fiber is 24 so it seems that at best carbon fiber is about equal and quite likely only about half as good at conducting as steel.

 

[Pdvdh]

DESCRIPTION
Type 416 stainless steel is a martensitic, free machining grade that can be hardened by heat treating to increase strength and hardness. The alloy exhibits machinability that is better than austenitic grades but sacrifices corrosion resistance.

CHEMISTRY TYPICAL
Carbon: 0.15 max
Phosphorus: 0.060 max
Silicon: 1.00 max
Manganese: 1.25 max
Sulfur: 0.150 min
Chromium: 12.00-14.00

PHYSICAL PROPERTIES
Density: 0.282 lbs/in3 7 .80 g/cm3

Electrical Resistivity: ohm-cir-mil/ft:
At 70 °F (21 °C): 343.0

Specific Heat: BTU/lb-°F (J/g-°C):
32 - 212 °F (0 - 100 °C): 0.110 (0.460)

Thermal Conductivity: BTU-in//hr-ft2-°F (W/m•K)
At 200 °F (94 °C): 172.8 (24.9)
At 1000 °F (538 °C): 198 (28.5)

Mean Coefficient of Thermal Expansion: µin/in-°F (µm/m-°C)
32 - 212 °F (0 - 100 °C): 5.50 (9.90)
32 - 600 °F (0 - 316 °C): 5.60 (10.1)
32 - 1200 °F (0 - 649 °C): 6.5 (11.7)

Modulus of Elasticity: KSI (MPa)
29.0 x 103 (200 x 103) in tension

Melting Range: 2700 - 2790 °F (1488 - 1530 °C)

8- Thermal Conductivity of Carbon Fiber
See my article on Heat Conductivity of Carbon Based materials including carbon fibre, nanotubes and graphene.

Thermal conductivity is the quantity of heat transmitted through a unit thickness, in a direction normal to a surface of unit area, because of a unit temperature gradient, under steady conditions. In other words it's a measure of how easily heat flows through a material.

There are a number of systems of measures depending on metric or imperial units.

1 W/(m.K) = 1 W/(m.oC) = 0.85984 kcal/(hr.m.oC) = 0.5779 Btu/(ft.hr.oF)

This table is only for comparison. The units are W/(m.K)

Air .024
Aluminium 250
Concrete .4 - .7
Carbon Steel 54
Mineral Wool insulation .04
Plywood .13
Quartz 3
Pyrex Glass 1
Pine .12
Carbon Fiber Reinforced Epoxy 24
Because there are many variations on the theme of carbon fiber it is not possible to pinpoint exactly the thermal conductivity. Special types of Carbon Fiber have been specifically designed for high or low thermal conductivity. There are also efforts to Enhance this feature.

Yeah,
Gotta make sure the units are identical. I didn't produce charts because the only thermal conductivity value that's important is the one for the CF material the barrel manufacturer uses.

Too much plausible deniability without that. Which is just the way they prefer it. Otherwise, why haven't they lowered their big guns on me in this Thread? And the other one where I ripped them also?

I'll eat crow if they produce legitimate data that supports their claims. Would be worth it. But they won't. Because it doesn't exist.

 

[Browning300]

Yeah,
Gotta make sure the units are identical. I didn't produce charts because the only thermal conductivity value that's important is the one for the CF material the barrel manufacturer uses.

That's true but my point is carbon fiber is rarely if ever used for heat dissipation and often used for insulation in all kinds of applications so it seems unlikely to me that something with well known insulation properties suddenly makes an amazing conductor....

Composite made from carbon fiber and epoxy resin is a material with heat conductivity x 40 times less than aluminium and 10 times less than steel. Therefore the assumption may be made that carbon fiber is a very good insulator.

This table compares heat conductivity of different materials– including carbon fiber (Unit W/m*)

Material Heat conduction
Carbon fiber– epoxy composite 5-7
Steel 50
Aluminium 210

 

[Browning300]

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.

I think carbon fiber wrapped barrels have some clear advantages in some areas and like it or not I think they are here to stay. But give it some time and let the fad wear off a bit and maybe people will be more willing to admit that carbon fiber is not a magic substance that exudes every position trait one could ever hope to find in a barrel material with no trade-offs at all.

 

[Pdvdh]

Yes. You provided some good information, and pointed discussion too. Wasn't trying to dismiss that or minimalize it.

Just that folk that wanna believe enough to argue about it will continue with the "what if" plausibility until the hammer finally falls. Which requires the actual thermal conductivity of the carbon fiber wrapped around their CF barrel.

Already been one comment that just because the carbon wrap doesn't transfer heat efficiently radially doesn't mean it doesn't dump a $hitload of heat in the longitudinal direction.

I believe in fairy tales too...

Thanks for posting that material. It's difficult to get a hard answer on carbon fiber thermal conductivity, because it comes in many flavors. The CF barrel manufacturers use this to fuel their "runs cold as ice" propaganda.