Barrel contour on new build.

[JohnyRingo]

I am kicking around the idea of having a custom rifle built. It is going to be a 300 H&H Mag used for hunting elk and deer in Wyoming. I also like to go out and shoot rocks at long distances...maybe 3-5 shots at a time. I am trying to decide on either a carbon barrel or steel. I like the idea of carbon for weight, as most of my hunting involves quite a bit of hiking, but my hunting can be hard on equipment and especially barrels. I don't know how durable the carbon barrel is going to be.

If I go with carbon, it will probably be a Proof Sendero Light at 2 lbs 13 oz. If I go with a steel barrel, it will probably be a Bartlein. I am trying to figure out the contour to keep the weight down, but not sacrifice accuracy. I am thinking a heavy sporter (#3 at 3.5 lbs) with flutes or a medium sporter (#2B at 3.2 lbs). Will I be happy with the accuracy of the these two profiles of steel barrels? I'm expecting to get close to 1/2 MOA. I can shoot 1 MOA with factory rigs all day long.

 

[martinakl]

watch this:


About 3 minutes in is where it gets good.

 

[Shane Lindsey]

I've got a Bart .308 1-10, 3B fluted waiting to be worked. I think this is a good weight for walking, but also consistent enough for stability. Magnum contour on a non-magnum case works well too.

I've got a 308 win with a 20" carbon and not sure I would do that again. I don't know if the carbon cools as it is advertised. Mine stays hot for a good bit after shooting. I think this is affecting things.

 

[LeddSlinger]

I just did a 300 Norma Mag Improved with a 26" Proof carbon barrel in Sendero contour. Sits in an AG Composites "Chalk Branch" carbon fiber stock. AG provides a barrel inletting option specifically for the Proof carbon contours. I added a picatinny rail on the end of the stock.

Kelbys Atlas Tactical - Lapua action
MB&M Titanium 4 port Beast brake
PT&G DBM with 5 round aics mag
Bixn' Andy TacSport PRO trigger.

Total weight is just a hair over 7 lbs without optic and bipod. Recoil is nothing with the Beast brake. Would be perfect for what you want to do. Of course you wouldnt need a Lapua size action for the 300 H&H, or a even a custom action for that matter. The carbon fiber barrel/stock, and titanium brake are the good weight savers.

 

[Highvoltage]

I agree with first post, I'd never do another carbon barrel. It holds the heat forever. If your someone who don't reload and your shooting factory ammo it's fine( try few different factory loads) but if your a reloder where your constantly tweaking things and shooting multiple loads carbon barrels take forever to cool. Thus making your load development very exaggerated and long. Btw my barrel is a sendero light proof

 

[lancetkenyon]

Lighter weight but stiff? Proof. I have 5 now. No real heavy hitters, but have shot probably 30 other CF barreled rifles. Almost every one has been extremely easy to tune. From 6CM to .300NM. All have shot fantastic. I like them....a lot.

As for heat, I have not done any testing of a CF wrapped barrel. But for a hunting rifle, who cares? Only the first shot counts anyway. And cold bore shift seems to be non-existent with all of mine.

First 3 shots out of one of mine (65SS w. 156 Berger) from this weekend at 200 yards were all within .25". I called it good and put it away.

Another speed demon of mine, never seemed to even warm up at the steel chamber end shooting 3 shot groups every 30 minutes. And after 12 rounds, put down a .3××" group at 200 also.

Not very scientific, but works for me.

 

[LeddSlinger]

I agree with first post, I'd never do another carbon barrel. It holds the heat forever. If your someone who don't reload and your shooting factory ammo it's fine( try few different factory loads) but if your a reloder where your constantly tweaking things and shooting multiple loads carbon barrels take forever to cool. Thus making your load development very exaggerated and long. Btw my barrel is a sendero light proof

Total BS.
Any barrel will heat up quickly and will need time to cool, especially if shooting larger cartridges. Proof carbon barrels dont hold heat any longer than anything else. The front of the chamber breech is where heat is a concern. Proof barrels have steel breeches just like every othe barrel out there.

 

[rustyshackleford]

I haven't spent much time in carbon barrels or had much interest. I'm sure it achieves the goal of providing an equally stiff barrel at a lower weight than a steel counterpart. However, I don't see how it could dissipate heat as quickly as a steel barrel or how it couldn't heat up more quickly. Maybe it's less affected by heat with regard to cold bore shift but all things being equal there's less steel to absorb and dissipate the heat and carbon fiber is not a great conductor. My vote is for a midweight steel barrel

 

[JohnyRingo]

I haven't spent much time in carbon barrels or had much interest. I'm sure it achieves the goal of providing an equally stiff barrel at a lower weight than a steel counterpart. However, I don't see how it could dissipate heat as quickly as a steel barrel or how it couldn't heat up more quickly. Maybe it's less affected by heat with regard to cold bore shift but all things being equal there's less steel to absorb and dissipate the heat and carbon fiber is not a great conductor. My vote is for a midweight steel barrel

I am kinda leaning that way. I see that Bartlein barrels are the most popular among professional shooters. To keep it as lightweight as possible, I am researching the #2B and #3 contour barrels to see what the accuracy of these barrels are.

 

[ntsqd]

From engineering resources on the net a CF/epoxy composite transfers heat ~2.25 times faster than does carbon steel and ~3 times faster than 416 SST. At least the example CF/epoxy composite that I found did.

However, the heat has to 'jump' from the barrel steel to the CF tube and that can be significant insulation depending on the exact construction. If there is an air gap between the CF/epoxy and the barrel it will be a pretty effective thermal insulator.

 

[rustyshackleford]

I can't find anything saying that. I'm sure there are exceptions but this seems to be the norm

 

[ntsqd]

CF/epoxy thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=0342a5fc8a79454f87dbd1eb42aedc47
514 BTU-in/hr-ft²-°F

4140 Carbon Steel thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=07d1795c3f034c97b52cccda78ae1409
296 BTU-in/hr-ft²-°F @Temperature 212 °F

416 SST thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=429d92bbf4374fcba39d7e668635803e
173 BTU-in/hr-ft²-°F@Temperature 212 °F

I see that I used the wrong number for 4140, what I thought was 110°F (trying for closest to ambient) was actually 1110°F, so CF/epoxy's conductivity is only ~1.74 times that of 4140 at the closest comparable temperatures.

 

[Quicksilver338]

I just did a 300 Norma Mag Improved with a 26" Proof carbon barrel in Sendero contour. Sits in an AG Composites "Chalk Branch" carbon fiber stock. AG provides a barrel inletting option specifically for the Proof carbon contours. I added a picatinny rail on the end of the stock.

Kelbys Atlas Tactical - Lapua action
MB&M Titanium 4 port Beast brake
PT&G DBM with 5 round aics mag
Bixn' Andy TacSport PRO trigger.

Total weight is just a hair over 7 lbs without optic and bipod. Recoil is nothing with the Beast brake. Would be perfect for what you want to do. Of course you wouldnt need a Lapua size action for the 300 H&H, or a even a custom action for that matter. The carbon fiber barrel/stock, and titanium brake are the good weight savers.

View attachment 152453

Great looking rifle, what bipod are you using?

 

[rustyshackleford]

CF/epoxy thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=0342a5fc8a79454f87dbd1eb42aedc47
514 BTU-in/hr-ft²-°F

4140 Carbon Steel thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=07d1795c3f034c97b52cccda78ae1409
296 BTU-in/hr-ft²-°F @Temperature 212 °F

416 SST thermal conductivity:
http://www.matweb.com/search/DataSheet.aspx?MatGUID=429d92bbf4374fcba39d7e668635803e
173 BTU-in/hr-ft²-°F@Temperature 212 °F

I see that I used the wrong number for 4140, what I thought was 110°F (trying for closest to ambient) was actually 1110°F, so CF/epoxy's conductivity is only ~1.74 times that of 4140 at the closest comparable temperatures.

Where does it say the temperature for the carbon fiber? I see a conductivity listed but no temperature.