Carbon Barrel cracked??

LRTalley · Aug 29, 2024

I have a Bartlein CF barrel chambered in 300 W.M.
Sent it to be put in a cryogenic chamber to relieve any existing stress in barrel, upon unboxing I found the carbon cracked completely through in 2 separate spots.
Also sent a Proof barrel chambered with same reamer to have the same process done and it looks the same as it did when I sent it off.
How big of an issue/problem is this and has anyone experienced the same before?
Thanks in advance.

Krob95 · Aug 29, 2024

@Frank Green

lash · Aug 29, 2024

LRTalley said:
Sent it to be put in a cryogenic chamber to relieve any existing stress in barrel,

Uhm, why?

kthomas · Aug 29, 2024

lash said:
Uhm, why?

I bet @Frank Green is going to love that

Long Range 338 · Aug 29, 2024

lash said:
Uhm, why?

x10…. Stress relieving is for barrels that are not cut rifled.

GIXXER2000 · Aug 29, 2024

$$$$$$ down the drain. Should have contacted Proof or Bartlein before down something like that.

Coejro · Aug 29, 2024

Certainly been a long time since my materials engineering classes. But carbon fiber is fairly resistant to thermal change. Steel less so. Between 5 and 10 times less so. So as you cooled the barrel, the carbon fiber shrank linearly 5x to 10x less than the steel, and that pressure from the 2 shoulders of the barrel compressing inwards on the CF is likely what caused what looks like partial delamination.

Others with way more experience than me will likely chime in, but I’m honestly more surprised that the proof isn’t showing issues, I’d check it much more closely.

ETA: fixed some autocorrect

3rdfocal · Aug 29, 2024

Metal contracted from being so cold and the carbon didn't? The 2 are bonded to each other so it caused the carbon to crack?

If the cracks are mostly cosmetic and it's still safe to shoot, I cant imagine it's gonna shoot well.

ZY100 · Aug 29, 2024

Oh my. I think you will have a sad panda face…but curious what Frank says.

It’s implied, but confirm the Proof was CF?

Sorry,
ZY

Ps. A little surprised the company cryo’d these—and they didn’t tell you before shipping there was an issue. Where they a gun-related company?

NateVA · Aug 29, 2024

Evintos · Aug 29, 2024

You just learned an expensive lesson. If you can, you should get a refund and get them to pay the cost of replacement barrels from whoever offered the cryogenic treatment for a carbon wrapped barrel. They should've told you it can't be done.

The carbon fiber matrix, commonly known as resin, is what failed (cracking and debonding).

Not worth the effort to try and salvage.

Huskydriver · Aug 29, 2024

That is a major issue

LRTalley · Aug 29, 2024

lash said:
Uhm, why?

Wasn’t very impressed with how it shot compared to my other steel barrels. If it’s only a cosmetic issue then I couldn’t care less, and will put it back together and check to see if it improved any

HerCoStarNTheBeaverPictur · Aug 29, 2024

A little duct tape should do the trick. Send it

Supersubes · Aug 29, 2024

It would never have occurred to me in a million years to stress relieve a bartlein. Wow! What a way to set fire to $1000 bucks.

6brshooter · Aug 29, 2024

Supersubes said:
It would never have occurred to me in a million years to stress relieve a bartlein. Wow! What a way to set fire to $1000 bucks.

Dude, that was the definition of "fuck you money."

diggler1833 · Aug 29, 2024

kthomas said:
I bet @Frank Green is going to love that

Yeah, but he's probably not going to jump in the thread and suggest that the customer is ignorant. Bad for business and all.

That's everyone else's job.

Huskydriver · Aug 29, 2024

HerCoStarNTheBeaverPictur said:
A little duct tape should do the trick. Send it

Darryle · Aug 29, 2024

I was part of a project that involved wrapping Titanium spools in raw carbon and glass, the cure cycle would cause a disbond almost every time, regardless of ramp rates or cool down process, dissimilar materials are a bitch because of thermal growth rates not being equal.

It was an exhausting 7 months working on that project, ironically, we didn't experience the same failure rates with stainless or carbon steel spools, but the weights were deemed unacceptable.

GenericBadGuy · Aug 29, 2024

@Frank Green talked about cryo here: https://www.snipershide.com/shootin...-barrels-cryo-treatment.7132585/post-10345364

4O6shootist · Aug 29, 2024

So Bart uses a 3rd party company to wrap the turned down blanks. They're the worst finish of any carbon barrel I've personally put hands on. They're rough, splintered, the epoxy has voids(like you have here) Take a microfiber cloth and wipe down the barrel twisting with the direction of the carbon wound wrapp, it'll grab the loose fibers and stick em in ur hand, or grab fibers and stick the towell. I know 3 cerakote shops that only do the bart carbons with low temp air cure paint, as the standard oven temps bleed the resin out the shoulders of shank and muzzle. Also, the carbon will pull away from the shoulders at the ends at typical oven cure drying temps. I've had 4 Bartlein carbons, and the exterior finish on my first one was pretty decent, still some loose splintering fibers, but the last 3 were poor. HARD PASS for me moving forward.

3rdfocal · Aug 30, 2024

4O6shootist said:
So Bart uses a 3rd party company to wrap the turned down blanks. They're the worst finish of any carbon barrel I've personally put hands on. They're rough, splintered, the epoxy has voids(like you have here) Take a microfiber cloth and wipe down the barrel twisting with the direction of the carbon wound wrapp, it'll grab the loose fibers and stick em in ur hand, or grab fibers and stick the towell. I know 3 cerakote shops that only do the bart carbons with low temp air cure paint, as the standard oven temps bleed the resin out the shoulders of shank and muzzle. Also, the carbon will pull away from the shoulders at the ends at typical oven cure drying temps. I've had 4 Bartlein carbons, and the exterior finish on my first one was pretty decent, still some loose splintering fibers, but the last 3 were poor. HARD PASS for me moving forward.

Agree, the finish is total garbage. I handle mine very carefully cause I'm scared I'm gonna take a glass shard through the hand. I won't buy another one until they fix that.

Now I would never have cryo'd carbon barrels... but I'm not surprised to see the proof survive it and the bartlien fall apart. The quality of the carbon work isn't even comparable.

Frank Green · Aug 30, 2024

To the OP…. Give us a call next week. I’m gone for the weekend now. I’ll talk to the carbon guys and see what we can do with it.

Yes… why did you have it cryo’d to begin with? The material is already heat treated and double stress relieved. Cryo for all I’ve seen does nothing for accuracy, cleaning or barrel life. That goes back to the quality of the barrel to begin with. I’ll say back in the day when we messed with cryo a lot… I seen one if not two barrels after they were shot and then had a cryo done to them didn’t shoot the same? It’s also not a cure all for barrel that doesn’t shoot. You can try it if you can get it done inexpensively cost wise but don’t get your hopes up.

Two the last two posts…. Way in the beginning to now the way it’s done is pretty different. Also shortly after starting it the carbon guys changed a couple of things and after seeing issues… we had a sit down about what was going on… changes where made and since then things have been pretty consistent. Also over the years I’ve seen issues with Proofs as well.

To me the cfw barrels… you want to save weight.. change the contour and skip the cf and save your money. If you like it because you think it looks cool… knock yourself out. It’s like fluting to me. It’s cosmetic. It does nothing for barrel life or accuracy. I also don’t like something different touching my barrel you have another variable to deal with if there is an issue.

Later, Frank
Bartlein Barrels

GIXXER2000 · Aug 30, 2024

I have had 1 carbon barrel 6.5 cm and seen 2 others. I have never seen a carbon barrel shoot a 5 shot group under 1/2. I been told they can it's just I have never seen it. My barrel would shoot great 3 shot groups but never a 5 shot group. I try 7 different 6.5 bullets and had the same result. This is why they are great for hunting. I will say there was very little if any cold bore shift so that is good.

6brshooter · Aug 30, 2024

Frank, your last paragraph echoes what I've been saying to friends that want carbon barrels. Get a sporter wgt barrel and save the 500+$ over a carbon. Seems they are billed as for hunting, but so are shorter wgts. I've never needed more than 2rds in a hunting situation, so the extra stiffness of a fat carbon isn't gonna be too useful.

I too have shot a few carbon barrels of buddys. They would shoot really nice for 3ish shots, but the next 2 rds would open up and turn a cloverleaf hole into a 3/4" group. Consistently and with different handloads.

kthomas · Aug 30, 2024

6brshooter said:
Frank, your last paragraph echoes what I've been saying to friends that want carbon barrels. Get a sporter wgt barrel and save the 500+$ over a carbon. Seems they are billed as for hunting, but so are shorter wgts. I've never needed more than 2rds in a hunting situation, so the extra stiffness of a fat carbon isn't gonna be too useful.

I too have shot a few carbon barrels of buddys. They would shoot really nice for 3ish shots, but the next 2 rds would open up and turn a cloverleaf hole into a 3/4" group. Consistently and with different handloads.

It's not as bougie though

surgeon260 · Aug 30, 2024

The reason I choose carbon wrapped barrels for a hunting rifle is to have enough meat at the muzzle for threading. On a 338 with 3/4" threads, you are pretty much limited to truck axle barrels, and carbon saves you a couple pounds. If you don't care about threading for a can, stick with steel.

CMP70306 · Aug 30, 2024

6brshooter said:
Frank, your last paragraph echoes what I've been saying to friends that want carbon barrels. Get a sporter wgt barrel and save the 500+$ over a carbon. Seems they are billed as for hunting, but so are shorter wgts. I've never needed more than 2rds in a hunting situation, so the extra stiffness of a fat carbon isn't gonna be too useful.

I too have shot a few carbon barrels of buddys. They would shoot really nice for 3ish shots, but the next 2 rds would open up and turn a cloverleaf hole into a 3/4" group. Consistently and with different handloads.

I did a 20” .223 barrel with the lightest contour that I could put 5/8”x24 muzzle threads on, it came out to 55 oz which was a pound heavier than my 20” 7 PRC barrel.

Terry Cross · Aug 30, 2024

Evintos said:
. . . . . you should get a refund and get them to pay the cost of replacement barrels from whoever offered the cryogenic treatment for a carbon wrapped barrel. They should've told you it can't be done.

I don't have a dog in this hunt but I would say that while the Cryo company could have warned the customer about CF, the vast majority of the responsibility should fall back to the customer.

Anybody that knows how to even pronounce Cryo likely knows what it entails.

Who is to say that the Cryo vendor hasn't done hundreds of CF wrapped barrels with no prior issues. Lots and Lots of variables at play there. The barrels were sent for a deep freeze cycle and that is exactly what the Cryo vendor provided.

Too many people wanting to be reimbursed for time and damages lost due to their own poor decisions.

Evintos · Aug 30, 2024

Terry Cross said:
I don't have a dog in this hunt but I would say that while the Cryo company could have warned the customer about CF, the vast majority of the responsibility should fall back to the customer.

Anybody that knows how to even pronounce Cryo likely knows what it entails.

Who is to say that the Cryo vendor hasn't done hundreds of CF wrapped barrels with no prior issues. Lots and Lots of variables at play there. The barrels were sent for a deep freeze cycle and that is exactly what the Cryo vendor provided.

Too many people wanting to be reimbursed for time and damages lost due to their own poor decisions.

If I take my truck to a mechanic, the mechanic says he can do the work that I want done and ends up damaging a part of my truck while "completing" said work, who's liable? If there's a liability waiver in place with fair warning that the process could damage the item, then I would agree that the responsibility falls upon the customer.

Carbon fiber/Matrix/Resin cracking and debonding under cryogenic temperatures is a known thing even with the inclusion of nano silica (or other nano particulates with low thermal expansion) filler in the resin. Science has been trying to overcome this issue for a long time for other industries.

A vendor that specializes in the process should've rejected the order. This seems more to me like backyard cryogenics with a vat of liquid nitrogen.

Terry Cross · Aug 30, 2024

Evintos said:
A vendor that specializes in the process should've rejected the order. This seems more to me like backyard cryogenics with a vat of liquid nitrogen.

We can find examples to back up both circumstances.
Mechanics put lift kits on trucks ALL THE TIME knowing that 90% of those trucks are going to prematurely blow out ball joints., etc. etc..

Don't get me wrong. I think they should have rejected it too. I just don't think they are more responsible than the person sending such parts in to begin with.

GBMaryland · Aug 30, 2024

GIXXER2000 said:
I have had 1 carbon barrel 6.5 cm and seen 2 others. I have never seen a carbon barrel shoot a 5 shot group under 1/2. I been told they can it's just I have never seen it. My barrel would shoot great 3 shot groups but never a 5 shot group. I try 7 different 6.5 bullets and had the same result. This is why they are great for hunting. I will say there was very little if any cold bore shift so that is good.

My MOBB Bartlein CF done by Mission Specific doesn't have any issues putting bullets in the same hole. Great BBL.

The Proof and PVA BBLs I've had all do great as well, though the Proof's are all slower.

kthomas · Aug 30, 2024

@LRTalley - if I was you, I would go and talk to the cryo company now. It was their service that ultimately ruined your barrel, while it was in their care. They need to take care of you. IMO, its their responsibility to make this right. That barrel didn't arrive to them in that condition, so for it to come back in worse condition is completely on them.

Yes, it was foolish of you to take a high quality barrel like a Bartlein and have it cryo'ed. But we all do foolish things from time to time. Anyone who claims that they haven't done something stupid in here is lying.

Consider this a lesson learned, and hopefully not an expensive one.

GBMaryland · Aug 30, 2024

I might consider cryotreating a button rifled barrel, but a cut rifled barrel?

Baron23 · Aug 30, 2024

Just my view and not a comment on anyone's particular love or hate of CF barrels...but I too don't see the value.

If on a PRS barricade/BR/bench and prone target gun who cares about the weight and a heavy steel barrel does, to my uninformed mind, offer a greater heat sink that a slimmed down steel barrel wrapped in CF.

Now...I don't climb 6k' mountains to hunt....I'm not a WY or similar mountain hunter in any respect of the term....but in a typical hunting situation (not varmint eradication) you are talking what...maybe two shots max. So, if weight is a concern, just get a slimmer steel barrel. and even for .338, TBAC Magnus comes with 5/8" x 24 and even 1/2" x 28 (if I read TBAC's spec's right)

They may be a good option for off-hand HP Silhouette type shooting where you will have strings of fire and weight is an issue.

This is just my thinking on the subject...but most people laugh hysterically at my thinking in general! haha

Cascade Hemi · Aug 30, 2024

jbuck88 · Aug 30, 2024

I spent a long time calculating the diameters at different lengths for steel barrels to meet the minimum diameter to thread for a supressor. Decide how much weight I needed to add in order to make the diameter requirement. Then decide how much weight I could pull back out with fluting.

Carbon Fiber barrels have their place.

I have noticed that the finish on my proof's is different then the finish on my bartlein. Is one better then the other? I have no idea. They are both more accurate then I am.

surgeon260 · Aug 30, 2024

Baron23 said:
and even for .338, TBAC Magnus comes with 5/8" x 24 and even 1/2" x 28

Magnus is not a 338 can. But regardless, 1/2-28 on a 338? That leaves less than 60 thou of material around the bore. No thanks.

Baron23 · Aug 30, 2024

surgeon260 said:
Magnus is not a 338 can.

It is now.

https://thunderbeastarms.com/products/magnus

As for 1/2”, I mentioned only because it’s part of their offering.

5/8’s should leave you about .145 of barrel thickness at the muzzle threads. Now, I have no argument if you still feel that’s too thin. Your gun, you choices. Right?

Cheers

Cascade Hemi · Aug 30, 2024

Baron23 said:
It is now.

https://thunderbeastarms.com/products/magnus

As for 1/2”, I mentioned only because it’s part of their offering.

5/8’s should leave you about .145 of barrel thickness at the muzzle threads. Now, I have no argument if you still feel that’s too thin. Your gun, you choices. Right?

Cheers

5/8-24 leaves .1125" wall thickness. Wall thickness is calculated from the minor OD, not major OD.

Baron23 · Aug 30, 2024

Cascade Hemi said:
5/8-24 leaves .1125" wall thickness. Wall thickness is calculated from the minor OD, not major OD.

Thank you…was wondering about that.

Cheers

GBMaryland · Aug 30, 2024

Having a carbon fiber barrel takes a couple of pounds off and after going from one barricade to another during the ridge class, that gets tiring.

I for one haven’t noticed it be significant issues… and if you have a rifle that’s gonna be good for 2500 rounds. It’s probably worth doing.

I will say that the six Creedmoor I picked up in an MTU barrel is freaking heavy… but I am wondering given just how much those things wear out throats if there’s an advantage to having an MTU.

wade2big · Aug 30, 2024

GBMaryland said:
Having a carbon fiber barrel takes a couple of pounds off and after going from one barricade to another during the ridge class, that gets tiring.

I for one haven’t noticed it be significant issues… and if you have a rifle that’s gonna be good for 2500 rounds. It’s probably worth doing.

I will say that the six Creedmoor I picked up in an MTU barrel is freaking heavy… but I am wondering given just how much those things wear out throats if there’s an advantage to having an MTU.

Why would throat wear have anything to do with barrel contour? Maybe you can clarify what you mean.

ohiofarmer · Aug 30, 2024

wade2big said:
Why would throat wear have anything to do with barrel contour? Maybe you can clarify what you mean.

@GBMaryland can clarify, I’m sure he’s talking about having the ability to set the barrel back.

GBMaryland · Aug 30, 2024

Both actually… it’s a bigger heat sink, so you’re five or 10 strings won’t heat the whole thing up quite as much. Probably reducing wear a little bit…

Then, you can have it set back as well… PVA is right around the corner and they could easily clean that up for a couple hundred dollars.

DeathBeforeDismount · Aug 30, 2024

kthomas said:
@LRTalley - if I was you, I would go and talk to the cryo company now. It was their service that ultimately ruined your barrel, while it was in their care. They need to take care of you. IMO, its their responsibility to make this right. That barrel didn't arrive to them in that condition, so for it to come back in worse condition is completely on them.

Yes, it was foolish of you to take a high quality barrel like a Bartlein and have it cryo'ed. But we all do foolish things from time to time. Anyone who claims that they haven't done something stupid in here is lying.

Consider this a lesson learned, and hopefully not an expensive one.

Na. Dumb dumb asked for a service and they did it. They gave the customer exactly what he asked for. Consider it a lesson in doing due dillegence.

Darryle · Aug 30, 2024

Materials used in barrels have different thermal expansion and contraction properties, the more dissimilar, the greater those rates are. If cryo is the end all be all, why not do the barreled actions?

4O6shootist · Aug 31, 2024

GBMaryland said:
Having a carbon fiber barrel takes a couple of pounds off and after going from one barricade to another during the ridge class, that gets tiring.

I for one haven’t noticed it be significant issues… and if you have a rifle that’s gonna be good for 2500 rounds. It’s probably worth doing.

I will say that the six Creedmoor I picked up in an MTU barrel is freaking heavy… but I am wondering given just how much those things wear out throats if there’s an advantage to having an MTU.

I have a 26" light palma steel, it's the same weight as a benchmark sendero carbon, shoots better too. If a person wants lighter weight, run a light palma, still able to cut 5/8x24 for a muzzle device.

Shoots 700's · Aug 31, 2024

That was dumb

jthor · Aug 31, 2024

Your fault, not Bartleins. You put carbon fiber in cryo temps that is not designed to do so. Maybe try this once SpaceX makes carbon barrels.

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