Who makes the longest barrel for AR-15

[oldmanFCSA]

Quote:
ps an AR in .308 would be an AR10 - not 15.
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Wrong...
LOL, not completely wrong but not completely right. An AR in .308 certainly isn't an AR15 and by name one certainly is an AR10. They are basically AR10 pattern guns.

Come on, learn how to learn to use the quote function when replying. It isn't that hard.

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One of my AR-15's is 0.308, another AR-15 is 0.310, neither is AR-10 but my AR-10 is Armalite. (First two are 7.62X39, one is US made ammo for 0.308, other is for Wolf ammo for 0.310")

[oldmanFCSA]

Bart's correct about fluting...always reduces stiffness. Of course, the science exists. Simple h.s. physics.


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Reduces stiffness, but increases the surface area of the barrel to promote better cooling.

And all brainiacts know that warm materials bend easier, so cooler materials must be stiffer.

Thus a fluted barrel increases surface area, decreases temperature of barrel due to better cooling and results in a stiffer barrel.

"That's my story and I'm sticking with it !!!"




As with my dog, please yell "BANG" before firing a shot in my direction so I can go hide under the bed.

[JeepHammer]

I am selecting all the parts for my build before purchasing them.

I am looking to build a .308 AR that is as accurate as possible.

Since you didn't specify 'AR-15',
Just for general information,
The AR-10 was the platform for short .30 rounds,
Like the .308 Win or NATO 7.62x51mm.

Barrels can be had in about any of the .308 case formats from .22-250 to .300 Short Mag,
But by far the most useful is the .308 Win since ammo is everywhere for it.

In the late '70s Armolite produced a 'Rhodesian Special',
An AR-10 that was VERY accurate and fired the NATO 7.62x51mm round,
And did it VERY well.

Right now, Knight Armament makes the strongest AR-10 Format upper receiver that isn't steel.
A rigid top end for this round is a MUST if you intend to shoot long range and be accurate.

Armolite has a pretty rigid Flat Top upper,
The carry handle version is still too light and flexible for extreme range shooting,
And it's a CRAP LOAD cheaper than Knight.

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Be aware of what MAGAZINE the lower will accept.
Some use modified M14/M1A magazines,
Some use the Stoner Rifle (SR25) mags,
Some use oddballs that are kind of hard to find and don't feed well.
Just something to keep in mind...

Personally, I find the SR25 mags to feed better than the modified M14-M1A mags.

I am trying to find a barrel out there that is at least 26" with a 1:7 twist ratio and preferably fluted. Does anybody know a company or somebody who makes a barrel like this or one even longer?

This is the CORRECT DIRECTION!
Put your money into the barrel, since that is the first and foremost thing that will make the rifle accurate!

Worry about the 'Accessory' crap later.
If you don't base your rifle on a good barrel/bolt, there is no point in continuing.

Kreiger makes a pretty good barrel, but they want an arm and a leg for them.

Armalite makes a top end with barrel, and it's a Kreiger barrel, just not paying Kreiger retail prices for it.

DPMS makes an AR 10 top, but the barrel is just plain not up to any standards I'm aware of.
It's a lead slinger in my experience.

Twist rate should depend on what weight/bearing surface bullet you intend to pump through it.

Up to about 168 Gn. BTHP bullets most people use, 1:11.5 to 1:12 rate is about right.
If you go with a heavier bullet (I shoot 178 Gn. in my long range rifle) you want a little tighter twist.

Most accuracy bolt rifles that shoot the 168 Gr. bullets use a 1:11-3/4 twist rate.

Generally, a tighter twist rate (1:9) will work just fine with 168 Gn. bullets, and still shoot the heavier stuff with ease and accuracy.
It's hard to get 'Too Tight' of a twist,
While it's quite easy to get one that is too slow to stabilize the heavier bullets.

Barrel length,
Somewhere around 24" will be 'Optimum' for .308 rounds.
I don't see where a 26" would hurt anything, but won't get you any more muzzle velocity to speak of.

Short barrels are what to avoid,
It's VERY EASY to loose enough muzzle velocity to make the round ineffective at distance.
An 18" barrel will make the bullet transonic at about 500 to 600 yards, while a 20" barrel will keep the bullet hypersonic at well over 800 Yards.

I shoot 24" barrels most times, and the bullet is still stable and hypersonic at over 1,200 yards.