Barrels

[BBelzer]

Hello,

 

I just started to build my first and second ar10.  My lower and upper are about to come in from Aero and I was looking around online for barrels. 

 

One of the ar10 will be mine and another will be a friend that will be building his.  

 

We are looking for a fluted bull barrel. One SS and one Black.   Any thoughts on where?  I see AR15barrels. have them but I don't know how good they are.   Length would be around 20.

 

Thanks

[FaRKle!]

Welcome!

 

What barrel length are you looking for? 

 

Also, why do you want flutes? If you're going for bull profile, weight doesn't seem to be of any concern. Cosmetics?

 

Lastly, AR-10s are only made by Armalite and others can adhere to the AR-10 pattern, but what you're building is an LR-308 pattern .308 AR, not AR-10. Nomenclature matters because if you don't properly distinguish the difference, you'll end up with parts that are incompatible with each other.

 

Rainier Arms has some barrels you may be interested in.

Edited February 1, 2015 by FaRKle!

[survivalshop]

  Around 20" ?  Fulton Armory sells Krieger Criterion Barrels & as said , Rainier , with its own Barrels along with the other manufacturers Barrels they sell .  There's actually quite a few really good barrels out, for the 308AR market .

[washguy]

Why 20".....a good 16" or 18" will shoot out to 500 no problemo......these ar308s" get heavy real quick,and then become closet queens

for some folks...do yourself a favor..go to Rainier Arms and get an off the shelf in stock barrel.... save money save weight...have fun!

:) Wash

[unforgiven]

Welcome from Indiana brother.

[Hueblerking]

Anyone bite the bullet on a Proof Research barrel? Or any other carbon wrap barrels? I haven't even finished my first build (Fulton armory 20" upper on an 80% lower), and I'm planning my second. I thought one of these might be fun to try.

Anyone have a couch? My wife thinks I'm crazy...:-)

[D.R.D.]

I think Robocop's got a carbon wrapped barrel if I'm not mistaken

[Robocop1051]

I do. I have their older "Advanced Barrel System" or "ABS" wrapped barrel. It was their original hand wrapped job. So far it has worked well for me. I met with PROOF at the SHOT show this year, and they stated that their new machine wrapped barrels are even better. They even offered to re-wrap my old barrel.

PROOF used to use Mike Rock or Satern barrels. Both are super high grade stainless steel barrels. Now they make their own barrels, in house. They are just as good as ever.

If you want a bull barrel performance, without the weight, go for the PROOF. If you want a lightweight barrel, get an actual "lightweight contour" barrel.

My barrel is a true HBAR. It's .875 diameter at the rifle length gas block, on a 17" barrel.

[98Z5V]

They even offered to re-wrap my old barrel.

 

 

Holy Shat, that is cool.  Those guys are awesome.  <thumbsup>

[Robocop1051]

There's a fee... but they said it'd be minimal since the meat of the barrel is finished.

[98Z5V]

I see no need then - when you can beat the old version off a cinderblock, and crush it with the barrel.  It's tough enough.  <thumbsup>

[Hueblerking]

Thanks, Robocop.  I met Mike Degerness at the Dallas Safari Club show.  He seemed like a solid guy running a solid business,and I'm glad my spidey senses weren't off.  He mentioned that 5 companies merged to form Proof, and that they're working on studies to prove their barrel concepts - accuracy, durability, heat dissipation.  Can't wait to read more on them.

 

One of these is definitely high on the list for build two.

[survivalshop]

Robo , just how long did it take to get your Barrel again ?  <lmao>

 

 

 

   I couldn't help myself !

[Robocop1051]

Okay funny guy. Yes, it took me 16 months from time of order to delivery. That was a time when you had your barrel custom made to order. Now they have off the shelf inventory. I understand their turn around is extremely fast. Especially since NEMO and SI-D are almost exclusively using PROOF barrels.

Also... I don't think Mike is involved with PROOF anymore. I spoke with him several times when I was getting my barrel done. He is one hell of a guy, and walked me through step by step on the process. Despite the long wait, I never worried. His constant communication was extremely uplifting.

[BBelzer]

One of the barrels I'm open on. Fluting is more for looks besides it does lighten up the barrel.  I just find fluted barrels more to my likings.    Other barrel is for someone else and that's what he is picking.   In Iowa 308s are mostly bench rest range guns. We don't have a hunting season for rifles anymore.

[Hueblerking]

I did a fair amount of research on barrel features as I progressed towards my build. I'm an obscenely long way from an expert on this topic, but here is some of what I picked up.

My primary goal was accuracy, which I would guess is yours as well if you're talking bench gun. I thought a long bull barrel would be the way to go, but I actually want to hunt with this thing. Weight was an issue for me, so fluting was something I was interested in.

I ran across research paper that compared fluted to same diameter non fluted barrels. The non fluted won out on accuracy. They then shortened the barrels and did the same test. Same result. Rigidity was the key, and some rigidity was lost from fluting. If I can find the paper, I'll post a link. All that said...I still think fluting looks pretty sweet.

There is a debate that will probably outlive us over which is more accurate - long or short barrels. I think there is a reasonable argument on both sides. The longer the barrel, assuming same diameter, the greater chance of barrel whip (think traditional rod vs. fly rod in fishing). The shorter the barrel, the shorter the powder burn. That results in lost velocity and that (I gathered) could have an increasingly negative effect on accuracy as distance to target increases. I'm told the .308 is an "inefficient" round, so I went with a 20" to squeeze a little more out of it. How far do you want to shoot?

I opted to go with Fulton Armory after deciding I wanted to buy a complete upper. Their reputation impressed me, and they offered just about every feature I was looking for. I would have loved to buy a JP Riffles barrel, but they are pretty proud of them. If I had contemplated it in time, I might have gone for a proof barrel. Wait would have mattered though. I doubt they're anywhere close to 16 months these days, but waiting for this stuff is a special kind of torture. My upper shipped today...that may be why I can't sleep tonight. :-)

What's your budget, by the way? On the barrel & the whole build? Now add 30%. Now double it (for your second build). Hahahaha.

Fulton has a nice FAQ page, and one of their topics is barrel manf techniques.

In the end it's your rifle; that's the beauty of building one. Make a list of wants and questions. Then google the hell out of it. A lot of what you'll find is opinion, but so far, the guys on this forum have been pretty even handed about verifying or providing sound reasons to exercise caution about any topic I've wandered into.

Have fun. Post pics. Sorry if I droned on too long...

[Robocop1051]

I'm told the .308 is an "inefficient" round...

Fire this guy. Unfriend him. Refuse his calls. File a restraining order.... do whatever you have to do to never get his advice again.

If you need further advice on the efficiency of the .308, you can audit my freezer.

[DNP]

^^^^Still got a lot of squirrels left?

[mineralman55]

Geez, so much information. Add this question to the list. Who makes the shortest barrel length with a rifle length gas system?

[D.R.D.]

Cool relevant article Heublerking:  http://rifleshooter.com/2014/12/308-winchester-7-62x51mm-nato-barrel-length-versus-velocity-28-to-16-5/

[Robocop1051]

Geez, so much information. Add this question to the list. Who makes the shortest barrel length with a rifle length gas system?

Criterion makes a 16" rifle length

Mega and Nemo make a 18" rifle length

[Hueblerking]

D.R.D., that's an awesome article. Here's the one I was referencing: http://www.snipercountry.com/articles/realbenefitsbarrelfluting.asp

Robocop, I'm just gonna try to build something to prove him wrong. I have my work cut out for me. That's his rig on crimson's PSA build thread, and he shoots at that range 3-6 times a month. It's a 6.5x47.

Mineralman, great point. Never had to address that because I arrived at a rifle length barrel. I only recently learned (on here) that the carbine length can have cycle problems.

[crimsonfalcon07]

I'm not positive that his math makes perfect sense.  I've had a similar discussion about fullering in sword blades.  The way that the math works with regards to stiffness is that a fullered (or in this case fluted) piece of metal will be more rigid than another piece of identical dimensions and mass.  Therein lies the rub.  It has to be equal mass.  In his calculations, he doesn't use a fluted barrel of equal mass, which leads to flaws in his conclusions.  Thus, a fluted barrel WILL be stiffer than a light profile barrel of similar mass.  But it's going to be less rigid than a bull barrel of greater mass, although that bull barrel would be less rigid than a fluted barrel of equal mass to it.  The point of fullering or fluting is that it decreases weight while mitigating loss of rigidity.  So while it's wrong to say that fluting a barrel INCREASES rigidity, it will decrease weight while not significantly affecting rigidity.  It provides a good balance.  So it's ALSO wrong to say that fluting has no effect on rigidity.  Does that mean that fullering or fluting is necessarily bad?  No.  Are there other options?  Perhaps.  I'm planning on testing out the Teludyne Tech Straightjacket system.  They claim that their barrels are more rigid than a similarly sized bull barrel, but are lighter weight, and the proprietary resin or whatever that they use wicks heat away from the barrel.  Because it's got a lot of surface area, it would then theoretically dissipate heat more effectively.  Might be snake oil, and it's certainly expensive, but the math checks out for me, provided that the filler material does what it's supposed to.  Materials science has certainly advanced to a sufficient point that it's possible.

It's also flawed to say that the surface argument is complete fallacy.  It's not.  While he's right to say that proximity to the bore also has an effect on the rate of transfer of heat to the outside of the barrel, it's also true that surface area IS increased by fluting and surface area DOES have an effect on rate of transfer of heat to the external environment.  Both are factors in cooling the barrel.

I suspect that the next big advance in barrel tech will involve carbon fiber nanotube or graphene, or some combination thereof.  Carbon fiber nanotubes enhance rigidity substantially (and in fact, AR500 has made IIIA body armor out of the stuff), and also have a very high heat transfer rate (something like 6 times higher than steel is theoretically possible, although it tends to be only twice as much).  It would be interesting to see a barrel made out of a crucible powder steel like 3V or something similar (for its MUCH higher wear and temperature resistance and superior carbide construction), wrapped with a double helical carbon fiber nanotube weave, maybe suspended in graphene (which can transfer heat many times faster than steel).
 

[unforgiven]

Well said brother,I would also suggest that the lines running parralle to the barrel with more metal thickness would provide the ridgeidity of the barrel.That's just looking at it from a mechanical stand point.

[Hueblerking]

I'm no physicist; I don't know if the difference between mass and weight matter when we're talking barrels. I am curious, though, if someone here does know.

From my lay perspective, the article I posted and crimson are basically saying the same thing on rigidity. With similar weight barrels, the fluted barrel will be more rigid. A heavy barrel loses some of its rigidity when flutes are cut into it.

A light weight barrel cools faster than a same weight fluted barrel, but that fluted barrel will cool faster than a bull barrel with the same outside diameter.

Finally, some cool space age $hite will probably and may be already offering the best of both worlds.