My experience: BSF Barrels May Experience Substantial Thermal Drift.

[centerfire]

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

You're right, I don't believe it. The PR CF barrel weighs 2.2lb by itself. My rifle with a lighter HG and much lighter scope weighs 9.5lb without a bipod. I could drop a few ounces with a different stock but I still wouldn't be close to 8.5lb with an Atlas bipod.

[bj139]

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...

Still much faster than SS.
Proof Research must have figured out how to get the lay of the CF to maximize the heat transfer.

[Kswhitetails]

Tightly wound CF with a thermally resistant plastomer in the epoxy resin would seem doable. I'm not a scientist though, disclaimer alert - theory inbound.

https://hackaday.com/2013/10/01/x-winder-carbon-fiber-wrapping/

[StoneHendge]

From Proof's website:

"Our helical wrapping pattern favors the longitudinal thermal diffusivity of the carbon fibers (along the length of the barrel) allowing them to more efficiently dissipate heat emanating from the barrel rather than insulating it.

Because our rifle barrels are engineered for thermal performance, they also move heat very effectively through the wall (thickness) of the barrel, greatly increasing heat transport and resulting in barrels that cool faster and maintain accuracy over longer sessions of fire."

I might use that as a line - "Hey Baby, want to check out my barrel's longitudinal thermal diffusivity?"

[grayfox]

Still much faster than SS.
Proof Research must have figured out how to get the lay of the CF to maximize the heat transfer.

Adding in the comment below about longitudinal heat movement yadda yadda (half of my brain is already asleep 8:30pm hahaha), I'd agree they do. Just goes to show that some quality and engineering thought in the design can produce results... Wasn't trying to say it can't be done, but it reinforces the observation that mfrs will differ in their ability to deliver. All of which is why they can charge more $$ for a quality barrel.
Congrats to those who go that route and get the bughole results..!

[Sticks]

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

You sure about that?

http://www.65grendel.com/forum/showthread.php?17462-PF-Bartlien-chamber-Cracking

I have had little to no advice or theories on the chamber. This is all new. It was a shooter, still is, just really concerned about the sudden .008 growth in fired case length. and raised ring just behind the shoulder on fired brass.

[grayfox]

Oh. Forgot about that thread...
Guess I need to be "reviewing - the situation..." (Fagan, "Oliver")!!

[SPQR 70AD]

Drinking and posting on the internet don't mix.

I would have to be very drunk to spend 500 on a barrel. others can do as they please

[bj139]

I would have to be very drunk to spend 500 on a barrel. others can do as they please

Kind of like this?

https://pickuptrucktalk.com/2018/06/sold-on-dealer-lot-107k-ram-2500-pickup/

[SPQR 70AD]

wow hard to believe but it is their money to waste if that's what they want