Best 308 barrel length for accuracy

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Asides from gaining extra velocity, does a 24 or 26 inch barrel have any accuracy advantage in a 308? Let’s say with a 1/12 twist. Thanks.
 
Asides from gaining extra velocity, does a 24 or 26 inch barrel have any accuracy advantage in a 308? Let’s say with a 1/12 twist. Thanks.

The standard for .308 shooters competing in F Class is 30” with a 1:10 twist for shooting 185g to 200g bullets out to 1,000 yards. Those guys are squeezing the absolute most in accuracy out of a .308 so that would be the benchmark
 
Length offers velocity, which may be critical at distance, as well explained in NB’s post above, but barrel length itself, as opposed to stiffness and/or harmonics, is no guarantor of accuracy. A very rigid bull barrel of 20” may offer significantly greater accuracy than a Sporter contour 24” barrel, for example.
 
Barrel stiffness is the key. If anything longer barrels are less accurate because it is harder to make them as stiff as a shorter barrel. The longer you make the barrel the greater diameter you need to achieve the same stiffness. If you don't need the length to get the speeds you need then shorter is generally better. 1000 yard shooters need 30" to get the speeds they need for bullets to remain stable in 308 at 1000 yards. If you're only shooting at 300-500 yards then 18"-20" is enough in 308.

Around 700-800 yards is where 308 starts running out of gas with conventional 22-24" barrels. Shooters have to go to extreme measures including extra long barrels and off the chart loads to get the bullets to remain stable out to 1000 yards. Other, more efficient cartridges will easily remain stable much farther than 1000 yards, and don't need a barrel longer than 20" to get there. And they are proving more accurate.
 
It was on a rifle I was looking at but not a core requirement for purchase.

Which rifle are you considering? And what do you want to do with it?

For me, the concern for accuracy usually means I’ll be shooting at longer ranges, so a slow twist doesn’t compute.
 
The US Army M24 has a 24" barrel. The standard SR25/MK11/M110 all sport 20" barrels. 16" Larue OBR's have won the Special Ops sniper match at Ft Bragg more than once, and I believe the new CSASS will also come with a 16" barrel. With the widespread use of suppressors nowadays, shorter barrels on both semi autos as well as bolt action rifles (in order to minimize overall length of the weapon system) have become more commonplace.
 
Tagged.

Currently have a PSA Gen II lower and looking at a PSA Gen III upper with 18" barrel for a hunting rifle capable of 500-600 yards while being reasonably lightweight (under 10lbs).
 
What JMR says seems to figure correct. I have a Savage bolt with a 24” heavy barrel, my 168grn bullets over a (not optimized) load of IMR4895 we’re running out of gas at just 700yds, hence my switch to IMR4064. I originally wanted to shoot to 1000, but after the test with the load above, I’ll probably relegate it to 800 max. Interesting thread.
 
With my rig and chosen powder, 32" was about where I hit diminishing returns on barrel length. I think 30" is probably about ideal, but if you shoot a lot, you should think to the future a bit. A barrel costs what it costs. My chosen barrels have always been krieger and they aren't cheap nor are they readily available. On my gunsmiths recommendation, I went with 32" rather than 30." With a .308 you're going to shoot the throat out long before you wear the barrel out, so at 32", this allows for knocking an inch off of the back once the throat is shot out. Then all your smith has to do is recut the chamber and refit the barrel.

I won't make any comments about whether the profile of the barrel has anything to do with the inherent accuracy of a barrel, but if you're going for long range and shooting competition either from a bag or bi-pod, heavy is good, if for no other reason than stability and recoil control.
 
Which rifle are you considering? And what do you want to do with it?

For me, the concern for accuracy usually means I’ll be shooting at longer ranges, so a slow twist doesn’t compute.

It was the sps varmint. It would be used for plinking and long range varmint from time to time. It has the 26 barrel on it. Probably won't pick it up but I was considering it. I have a bunch of 155 Sierra's MK that I could load for it but, as I said, probably won't pick it up.
 
It was the sps varmint. It would be used for plinking and long range varmint from time to time. It has the 26 barrel on it. Probably won't pick it up but I was considering it. I have a bunch of 155 Sierra's MK that I could load for it but, as I said, probably won't pick it up.

For what you’re after a 26” 1:12 would be just fine
 
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