Optimum .308 Barrel Length

[pollock28]

Alright I tried searching but couldn't come up with much to answer my particular question.
In a bolt action .308 what is the optimum barrel length? In terms of speed and accuracy? 20",22",24",26"? Whats the best? Looking for long distance shooting?

 

[R.W.Dale]

For long range shooting <300m+> you want as long a barrel as possible as every bit of velocity helps with the wind. Inside that range there's really no advantage to anything longer than 20" and in fact the shorter stiffer barrels may prove to be more accurate

 

[pollock28]

Cool i guess thats exactly what i was wondering. Thank You!

 

[GunTech]

Indeed, 'optimum' is an open ended question. You'll keep gaining velocity out to something like 54 inches, IIRC The again, and as krochus noted, a shorter barrel is stiffer. Also, the sorter the barrel, the less time the bullet is in the barrel and the lesser the chance of the barrel moving after firing.

Palma shooter routinely use 30 inch barrels. The remington 40x match rifle in 08 shipped with a 27.5 inch barrel. 26 to 24 inch barrels are the most common, but 20-22 inch barrels are showing up at a lot of tactical matches.

Ultimately, you have to look at the requirements. I shoot out past 1000K, and trimmed my 27.5 inch barrel back to 20 inches. I have no problem shooting at that range, and only lost a few MOA drop. In return I lost almost 3 pounds and have a much handier and better balanced rifle.

YMMV

 

[pollock28]

Yeah i guess i was specifically wondering if 20" was suffieciently stabilizing the bullet. But if you are shooting beyond 1000k it answers my question.
Thanks!

 

[Dr. Tad Hussein Winslow]

It depends highly upon the use and tolerable weight of the rifle (barrel profile/thickness).

For a fighting rifle or ultra-light hunter, 16-20". For a hunting rifle, around 21-22". For an all-purpose practical rifle, maybe 22-23". For a heavy bench rifle, anywhere from 24 out to 30", or maybe even more for some sort of crazy mammoth gun. After 30" though, the barrel thickness required to make it stiff enough to hold outstanding accuracy becomes not worth the tradeoff in size and weight, for the small velocity gains (not to mention the cost in finding a barrel maker that will do over 30).

Personally, for long distance shooting, I'd prefer a 26" barrel or more. For a fighting rifle, 20" is good - a bit muzzle heavy (relative to the 16 or 18 inchers), but worth it to help tame the recoil & blast. For an all-purpose gun or hunter, I'd want right at 21.5 or 22" for a short cartridge like .308 win.

 

[Jim Watson]

Well, the M14 and the Winchester M70 Featherweight have 22" barrels and I don't see any need to change for a military or hunting rifle. Maybe if you are working in tight quarters, a carbine length gun would be worth having.

For conventional target shooting, the longer the better, within reason. A little free velocity, longer sight radius for iron sights, and moving the noise farther away from your head are all assets. My F-T/R has a 28" barrel, largely because that was the longest Pac-Nor would make without charging extra per inch. But then it is for a scope sight, and the 30" or even 32" of a Palma rifle would not be much help.

Back when a few benchrest shooters used .308, the short stiff barrel approach paid off at their moderate ranges. One expert trimmed barrels 1/8" at a time and concluded that your best bet for tight groups was at or near a 21.75" barrel, due to the vibration nodes of a bull barrel.

GunTech made the choice for his tactical match rifle, paying "a few MOA drop" (and maybe more than a few MOA windage) for something easier to hump around.

 

[GunTech]

Stability has more to do with matching bullet to twist. I have a 1:12 and it will not stabilize anything heavier than 175gn SMKs. I've gone to 155 Lapua Scenars, which I can push at 2600 fps pretty easily. With a BC of just over 0.500, I can get to 1000 with about 36MOA from a 100 yard zero.

 

[pollock28]

edited: repealed my question.

 

[Jim Watson]

I am just shooting up my supply of 175 SMKs and have some 155 Scenars waiting in the wings. My 28" barrel is getting 2900 fps a grain below maximum powder charge. That is almost 250 fps faster than the 175... with nearly the same B.C. Grouping is as good and elevation is about 6 moa flatter at 1000.


My .308 barrel is a Pac Nor, chosen because they would make a DIY for Savage.
I have a Krieger on my .223 that is a very fine barrel.
Friend of mine has a Douglas and a Hart on his most used rifles and they are also very good. Anybody who thinks Douglas is old fashioned or second class and that a button rifled barrel has been obsoleted by the rediscovery of cut rifling is out of touch with reality.

I'd look at McMillan first for a good stock.

Lots of barrel and stock threads at
http://www.long-range.com/forums/

 

[The Wiry Irishman]

can get to 1000 with about 36MOA from a 100 yard zero.

Do you mean 36 inches? 36 MOA at 1000 yards is about 30 feet.

 

[Jim Watson]

Yup. 36 MOA.
Raise your sight by 36 inches at 100 and you will be close at 1000.

 

[glockman19]

My Remington 700 will have a 26" heavy barrel. My M1A has a 22" with 2" muzzle break. The M1A shoots clovers @ 100 yards 1" moa @ 200 yards and 4-6" @ 500 yards. I'll be curious to see how the longer heavier bedded bolt action will do.

I'll check back in a few weeks when teh a-bolt is built and let you all know. IMHO rifles are inherantly more accurate than their human users and any variance is that of human error.

 

[jbech123]

Do you mean 36 inches? 36 MOA at 1000 yards is about 30 feet.

Depends on the exact load, but for any load 36moa would be closer to getting you on paper at 1000 than 36 inches. if your rifle is sighted in for 100, 36 inches of holdover would barely get you to 400 yards, let alone 1000.

 

[rodregier]

I like 20" as a nice handiness factor if vehicle entry/exit isn't a major consideration. 20" also isn't too rude in the muzzle-blast department. Barrel length being too short isn't a real consideration in accuracy except in marginal twist rate/velocity situations.

Concur that if really long range is in the cards more barrel is generally a good thing.

I have a .308 with a 20" barrel in a hunting configuration, and a 24" for F/TR competition format for much longer range usage. I'm still very satisfied with the barrel length on each for their application.

 

[For Freedom]

I actually like 16.25" for deer hunting. Since I don't shoot at deer beyond about 300 yards it doesn't matter. It's handy in thick brush too.

 

[Ridgerunner665]

22 inches.

 

[The Wiry Irishman]

Yup. 36 MOA.
Raise your sight by 36 inches at 100 and you will be close at 1000.

I misunderstood - thought you were talking about grouping. Oops.

 

[atlanticfire]

I like my Savage FTR in 30". . . just my 2 cents.