My experience: BSF Barrels May Experience Substantial Thermal Drift.

[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]

This doesn’t sound promising for my barrel. I had them make me a custom 16” mid gas and waited like 7 months for it. Just got it the other day.

[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_c...ivity.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...

[centerfire]

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.

Mirage is a serious issue with a Proof barrel. In a 10 round string, the gas block externally doesn't get over ambient air temperature. It would not surprise me if in a cold environment, during slow firing, that every shot was a cold bore.

[Sticks]

More and more I am thinking of pulling the trigger to replace my Bartlien with a PR.

[centerfire]

More and more I am thinking of pulling the trigger to replace my Bartlien with a PR.

I've got a 6mm that is going to need a new barrel soon and it's probably going to be a Proof barrel. Unless you specifically need weight, the Proof is excellent. Also, from a custom LW barrel standpoint, the Proof is in line cost wise with a Bartlein or Krieger.

[grayfox]

More and more I am thinking of pulling the trigger to replace my Bartlien with a PR.

If that Bartlein still has life in it, I might take it off your hands.

[LRRPF52]

A buddy of mine just built a 20" Proof Grendel barrel on Seekins billet receiver/handguard set.

Spuhr mount with Leupold Mark 6, ATLAS bipod, you'll never believe what all that weighed in at....

8.6lbs

[Kswhitetails]

That's pretty top shelf stuff. I'd bet he's proud of that one, and should be. 8.6 lbs is crazy light for a 20", 34mm with a boatanchor, and bipod!

[SPQR 70AD]

I believe when some one charges 500 just for a barrel they are ripping you so to me they have no scruples. maybe the Chinese would get involved selling barrels for 49.99. after all they ship a forged MIA to Canada for 400 bucks as good as the 2000 dollars ones made in the US. Norinco was an excellent gun maker but got banned by Clinton I have some of their guns

[Kswhitetails]

I believe when some one charges 500 just for a barrel they are ripping you so to me they have no scruples. maybe the Chinese would get involved selling barrels for 49.99. after all they ship a forged MIA to Canada for 400 bucks as good as the 2000 dollars ones made in the US. Norinco was an excellent gun maker but got banned by Clinton I have some of their guns

Hmmm, seems many folks would dissagree with you. When considering how many barrels Proof sells around the country, to happy customers I'm reminded that sometimes paying more is understood. Scruples aside, if someone will pay more for something than I will, then there is a market for it; and I for one want more folks to feel free to fill it. This breeds competition and competition is the reaper of high prices. I'd rather pay for something at a high price - if the performance and service provided are worth it, than pay a lower price for something that provides inferior performance with no or unsatisfactory service. I'm pretty sure that the market (case in point - this thread) will ferret out the lesser performers and force them either into oblivion, or reducing their pricing to reflect it.

[grayfox]

Yes Proof barrels are on the expensive side, but that's b/c they are premium barrels. There are several good "value" barrels in mid-price range, and some pretty cheap ones too (think BCA et al), the cheaper ones seem to have several problems but even so they have made some good shooters too. My point in this, from 40+ years in an industry that had to (and has to) have high-quality high-grade steels (lives depend on it), is that good steel will cost you some coin but save you problems down the road as well. IMO some Chinese commodity-like goods may be ok, but I'm skeptical of ones for essential-quality roles...

Disclaimer I don't own any Proof barrels, I also don't own any chinese barrel either.

You can't fix bad or cheap steel.

In steel, you get what you pay for. And pedigree, heat-treatment, grain structure, % compositions, groove-cutting, etc, are all important. Think of the old MIM/powder metal parts and the issues they caused.

[StoneHendge]

A bit to busy to join in on the Proof discussion, but in their defense, I would like to hear what other barrels could do this with 5 shots at 100 yards:

[ATTACH=CONFIG]12322[/ATTACH]

And leave you banging your head against the wall to find out what is loose.

[NugginFutz]

A bit to busy to join in on the Proof discussion, but in their defense, I would like to hear what other barrels could do this with 5 shots at 100 yards:

[ATTACH=CONFIG]12322[/ATTACH]

And leave you banging your head against the wall to find out what is loose.

Since you asked...

300 Yards w/ American Gunner

BHW 264LBC


And this, also at 300 yards w/ American Gunner...



Larue Tactical 6.5 Grendel w/ ~75 rounds down the tube.

[centerfire]

I believe when some one charges 500 just for a barrel they are ripping you so to me they have no scruples. maybe the Chinese would get involved selling barrels for 49.99. after all they ship a forged MIA to Canada for 400 bucks as good as the 2000 dollars ones made in the US. Norinco was an excellent gun maker but got banned by Clinton I have some of their guns

Drinking and posting on the internet don't mix.

[StoneHendge]

Since you asked...

300 Yards w/ American Gunner

BHW 264LBC


And this, also at 300 yards w/ American Gunner...



Larue Tactical 6.5 Grendel w/ ~75 rounds down the tube.

What was loose? :p

[NugginFutz]

What was loose? :p

I believe it was the nut behind the scope ocular.