My experience: BSF Barrels May Experience Substantial Thermal Drift.

[grayfox]

No barrel can "reduce the heat" -- it could, however, dissipate the heat more quickly thus leaving the barrel and/or chamber cooler in temperature.

The deflagration/shot fired will generate the heat (energy) that it does, nothing can "reduce" that.

[StoneHendge]

No barrel can "reduce the heat" -- it could, however, dissipate the heat more quickly thus leaving the barrel and/or chamber cooler in temperature.

The deflagration/shot fired will generate the heat (energy) that it does, nothing can "reduce" that.

Yeah, that was my take. Even if it means it cools rapidly, it makes it sound like BS. And if they can't phrase their marketing correctly, who knows what else they can't do correctly.

[LRRPF52]

Guys, I'm trying to put myself in the shoes of this particular barrel vendor.

I'm sure they didn't put all this effort into making something that was garbage, and I'm seeing a sample size of one right now. Maybe I overlooked something.

I don't know these people, have no experience with them or their products, but would like to hope this was a one-off issue and lean to giving them the benefit of the doubt.

Has anyone else had experience with them?

When I see the thread title, I wonder if something like "My experience with a 6.5 Grendel BSF barrel" might be more gentlemanly of us.

What do you think, StoneHendge?

[StoneHendge]

Guys, I'm trying to put myself in the shoes of this particular barrel vendor.

I'm sure they didn't put all this effort into making something that was garbage, and I'm seeing a sample size of one right now. Maybe I overlooked something.

I don't know these people, have no experience with them or their products, but would like to hope this was a one-off issue and lean to giving them the benefit of the doubt.

Has anyone else had experience with them?

When I see the thread title, I wonder if something like "My experience with a 6.5 Grendel BSF barrel" might be more gentlemanly of us.

What do you think, StoneHendge?

No problem with title change I've cooled down (pun intended) and got my money back, but how about BSF Barrels May Experience Substantial Thermal Drift.

But that's the thing that got me. Everyone knows to be careful with carbon fiber from experiences with Christenson and that gave (and probably still gives) Proof Research baggage to overcome. BSF claims that their sleeve and hole design allows the barrel to cool. Maybe it does a little, but mine behaved like it was for the most part insulated. They claim to have spent 3 years developing it, to have set a new industry standard and to make it the "most cost efficient, accurate and versatile barrel on the market." The last part is what gets me. Everyone knows what they get with a Christenson - and that's fine for a big game hunter who wants something light to carry around the back country and impress his friends when he's only going to take a shot or two to fill his tag.

It was an easy 1/2 MOA shooter when cool. I was really impressed at first. I guess the drift it had when it got warm could have been caused by something else - maybe the sleeve connection or out of spec sleeve caused the barrel to warp. But I'm inclined to believe it was almost surely from being hot in the core since the insulating Faxon Carbon Fiber handguard added another 1-2 inches of drift when I did the same test with that handguard on.

If anyone else who has one is happy with theirs and they shoot it at a slow pace, I would NOT recommend doing what I did since it cant be good for the throat. But if anyone thinks they might use it from the prison guard tower someday when the zombies are crashing the fence, they should try my test. Because mine was outside of minute of zombie head and they would have gotten in.

Edit / Add: I've thought about trying the same with my Proof S'more barrel, but I can't let myself do it. Even if it doesn't (and I'm pretty sure it wouldn't since there is negligible drift if I do a 10 round mag in a minute), I don't want to burn that much powder that fast in a throat that will likely only last around 2500 rounds under normal fire.

[LRRPF52]

That sounds great StoneHendge. I changed the thread title based on your recommended description.

With the intent to ventilate the carbon fiber, it's possible they shot themselves in the foot with carbon surface area purchase to the OD of the barrel.

When dealing with two different materials that get thermally loaded in a short period of time, coefficient of thermal expansion and contraction are very difficult to mitigate consistently for desired behavior that is more reasonable in a single material type.

I'm not sure the holes are helping out here, but that's just speculation on my part.

[grayfox]

With the barrel being of (I suppose, having not owned one) a thinner steel and then CF wrapped on it for more stiffness and other benny's, heat removal through it can't be as great as air-cooling, to say the least. Right, the holes would allow more heat to escape but if you really need heat dissipation -- who makes it? I forget -- there's that radial-finned attachment riding the barrel that increases surface area and thus speeds the cooldown. Possibly even fluting, since it also increases surface area somewhat for the barrel...

Yeah, I'll confess CF barrels are outta my league, to me they're more of a novelty or one to play with once you've got all the other toys... more power to the guys who want to go that route, however.

[LRRPF52]

JP makes the radiators for their barrels, and they work.

[grayfox]

yeah. those are the guys, just couldn't recall who they were.

[bj139]

Here is a short article describing why they are trying to use carbon fiber for greater thermal conductivity (cooling).
When I saw the cooling slots on the BSF barrel I thought, WTF. It shouldn't need them.
Stiffness is another benefit.

https://christinedemerchant.com/carbon_characteristics_heat_conductivity.html

Here is another manufacturer that uses continuous carbon fiber and states the benefit of increased cooling rate.

https://www.proofresearch.com/the-products/barrels/

[A5BLASTER]

JP makes the radiators for their barrels, and they work.

Yes they do, very well indeed, only problem is that your handguards must be there's are one very close to the same size and shape.

[centerfire]

Guys, I'm trying to put myself in the shoes of this particular barrel vendor.

I'm sure they didn't put all this effort into making something that was garbage, and I'm seeing a sample size of one right now. Maybe I overlooked something.

I don't know these people, have no experience with them or their products, but would like to hope this was a one-off issue and lean to giving them the benefit of the doubt.

Has anyone else had experience with them?

When I see the thread title, I wonder if something like "My experience with a 6.5 Grendel BSF barrel" might be more gentlemanly of us.

What do you think, StoneHendge?

He was right though. BSF doesn't wrap barrels, the CF is a sleeve.

[subinoob]

[grayfox]

Here is a short article describing why they are trying to use carbon fiber for greater thermal conductivity (cooling).
When I saw the cooling slots on the BSF barrel I thought, WTF. It shouldn't need them.
Stiffness is another benefit.

https://christinedemerchant.com/carbon_characteristics_heat_conductivity.html

Here is another manufacturer that uses continuous carbon fiber and states the benefit of increased cooling rate.
https://www.proofresearch.com/the-products/barrels/

Wish I still had my materials science PhD guys around... had to leave them back at the agency when I retired...
I read thru the first one briefly and seems like CF could have good conductivity. Note however that it would not be the "Graphite" number (300-1500) but the (lower) CF one of 21-180. Maybe better than steel I would say but not orders of magnitude. I wonder if the tested setup is conductivity along the fiber or across a wrap of several fibers in a cylindrical volume, like would be as the exterior of a barrel... hmmm. Also what temp difference does it take to conduct across from the steel to fiber, across that boundary between the two...

I do wonder at the statement that conduction in metal comes via free electron motion (electrons don't have a lot of mass and so cannot convey a lot of thermal energy)... free electron contributions are more akin to electrical current, my understanding of heat flow is that it is via vibration of the atoms/molecules in the metal lattices, energy flowing from higher temperatures (higher vibes) to lower ones. That being said CF still might have a higher conductivity coefficient, its range (21-180) is both higher and lower than carbon steels (~68-80).

I also wonder at the actual, physical construction of the CF wrap... is it a series of fibers wrapped "tightly" or is it a weave of materials, or what... for steels, we know it is a continuous latticework of metallic material, no physical gaps (or very tiny micro-gaps, fractions of microns)... ie, a non-continuous material will have physical barriers for the heat to cross, one fiber at a time, whereas that is not so across the metal volume. This could make a difference and effectively slow the heat flow through a CF weave. I wonder if anyone has published actual test values of conductivity across the CF barrel, radially out, across the wrap as would be when it has to function in use...? Have we seen any test results on that? that would tell us a lot, but it could also vary from mfr to mfr since each one would have its own design specs.

[bj139]

I was surprised at the high thermal conductivity of carbon fiber as well.
But, as noted in the article thermal conductivity through epoxy is much less.

[grayfox]

me too. If it is a case, in the CF barrels, of heat flow from carbon fiber, across some epoxy, thru another strand of carbon, then epoxy, etc etc, the overall conductivity will be more similar to epoxy heat transfer coeff, not the CF'c coeff. Kind of like going 60 mph for a block, then hit a stop light, then another 60 mph for a block, then another stop light... what do you suppose the overall average speed is? not 60!! any teenager with a lead foot can tell you that...