Opinions On 308 Twist Rates

[67rschev]

I'm getting ready to order a barrel for a 700 build and would like to get your opinions on what twist rate and why . I did a search and I'm sure this has been beat to death , but couldn't find any definitive articles or threads to sway me one way or another . Why would one take a 1 in 10 over a 1 in 11 or vice versa . Mostly what I have come up with is the 308 cartridge is very forgiving , and both will shoot light and heavy weight bullets fairly evenly .

If it makes any difference , will be finishing at 22 inchs . What all do you say ?

 

[Zebra644]

Re: Opinions On 308 Twist Rates

What are you using the rifle for and are you going to reload?

 

[Wylie Custom]

Re: Opinions On 308 Twist Rates

What bullet are you wanting to shoot?

I use a 1 in 11.25 with great results with 168 to 180 grain bullets.

 

[nashlaw]

Re: Opinions On 308 Twist Rates

I have a 1/10 twister that does well with 168s up to 190s. A 1/13 goes up to 168gr bullets with no problems, but really shines with the 155s.

The 155s are a delight in a 12# rifle for a long day of shooting.

 

[creids98292]

Re: Opinions On 308 Twist Rates

Choose your prefered/heaviest bullet weight then choose a twist that will stabalize it suggested by the bullet manufacturer. with a 22" tube you will want to choose a little faster than if you were running a 26" tube due to lower mv. A 10tw will work up to the 190's for example per most manufacturers.
Chris
Benchmark

 

[67rschev]

Re: Opinions On 308 Twist Rates

The rifle is and will be used for target shooting at 100 to 800 yards , and possibly longer if I can find a longer range . The preferred bullet at this time is the 168 SMK , and I am sure has to do with the long factory headspacing of the Remington Varmint barrel. Have an array of 30 caliber bullets , from 155 to 200 grains that I have been working with . Been handloading for this piece since it was new and will shoot around MOA to 400 , but can be very inconsistent at times . It has the usual upgrades such as AI chassis , Jewell , great glass ect , and I think the stock barrel is holding my shooting back at this point in time . Will be stating over again working loadings back up when the barrel is installed and action worked . Was just wondering if there were any benefits either way , to sway me into one twist or another

 

[VonReich]

Re: Opinions On 308 Twist Rates

1-11.25 RH, a good 24" length should be fine.

 

[67rschev]

Re: Opinions On 308 Twist Rates

Thank you gents , pretty much what I was thinking . The 308 cartridge is much more forgiving than some, and seems to shoot well with a variety of bullet selections .

I can understand possibly going with a 1 in 10 , due to my length choice being 22 inch . Little more twist might be good with a shorter barrel to shoot the heavies , and still shoot 155s well

 

[spiritzerothree]

Re: Opinions On 308 Twist Rates

I run a 22" 1/10 rock creek, does great with everything from 155-208

 

[Shortdraw]

Re: Opinions On 308 Twist Rates

I just shot 220RN out of my 10 twist with good accuracy. 10 twist is super versatile, 155's on up.

 

[Rprecision]

Re: Opinions On 308 Twist Rates

1/10 twist 168's to 200's

I feel that a bit to much twist is better the just enough.

In a .308/7.62 your barrel life will be the same with either

 

[clmayfield]

Re: Opinions On 308 Twist Rates

I have a 1:10" and wish I had a 1:11". The only bullets that a 1:10" will stabilize that a 1:11" won't are too heavy for a 308 any way. A 1:11" will stabilize up to a 210 grainer just fine. Faster twist means that lighter bullets will not shoot as well. A 1:10" is also too fast for flat based bullets intended for pinpoint accuracy at <300 yards.

I chose the 1:10" thinking that it would give me max flexibility because it will stabilize all projectiles. It will... but given my chamber dimensions, if I use a bullet over 210 grains, there would be no room left in the cartridge for powder and I would need excessive jam or an excessively compressed load.

1:11" will give you max flexibility the only reason that I can think of to go faster would be for use with subsonics or if you had your chamber cut specifically for very heavy bullets... in other words, an extra long leade and a long action or a single shot.

 

[head2h2o]

Re: Opinions On 308 Twist Rates

My 1 in 11.25 and 1 in 11 both shoot 175's well. The 1 in 12 has always done well with the 168's.

 

[targaflorio]

Re: Opinions On 308 Twist Rates

Berger recommends a 1:13" or faster for their 168s. I chose 1:11 in a 22" barrel to shoot 175 and 178 grs. Does well.

 

[67rschev]

Re: Opinions On 308 Twist Rates

Thank you all for the real world input . If anything it has made my decision a little harder . One more question , has anyone ever had the ' Blue Puff ' halfway down range with an over twist barrel shooting a light weight ? I don't know if this happens with the size of the 308 caliber projectiles or not . I have a 1 in 6.5 service rifle that has warped some into oblivion mid flight , all though it was only 1 lot of Hornady's .

 

[Trevor]

Re: Opinions On 308 Twist Rates

I see you’re in Colorado, what elevation is your range at and do you plan to travel outside your state? Altitude has a huge effect on stability.. The higher up you are the less twist you need. The common twist around here is 11.25 I have this twist on one build and it shoots the 168 great.. I am at 300ft above sea level. You might be 3-5000ft ASL.. 2nd rule use the slowest twist you can get away with that still gives you a 1.4 SG (stability).. Slower twists put less torque on bullets which means possible less bullet failure. JBM has a stability program on it you can play with to find out where you are on the SG scale you can change the numbers on altitude, velocity, bullet length, temperature and barrel twist. You should be able to get away with as slow as a 13 twist

As for bullet blow ups I have seen it, looks pretty cool (as it wasn’t mine) typically they are caused by a bad bullet, tired barrel, screaming speeds and too fast a twist, and/or a combinations of all four.

My first thought was to find a different bullet as the 168 is a shorter distance design and may have been suspect out to 800 yards but again because you are in Colorado they should work fine.

Best of luck.
Trevor

P.S.
Some one else my be able to provide the JBM link as I can’t access it at the moment

 

[Graham]

Re: Opinions On 308 Twist Rates

You won't have to worry about altitude effect on stability, and you won't have to worry about blowing-up bullets. If you shoot a lot in very cold weather you might want a fractionally higher twist rate than otherwise, but an 11-12 should work fine unless you want to shoot subsonics or cut the barrel to less than 18" of rifling and intend to shoot it to 90% of its supersonic range.

http://www.riflebarrels.com/articles/long_range_shooting.htm
http://www.riflebarrels.com/articles/bullets_ballastics/bullet_imbalance_twist.htm

 

[67rschev]

Re: Opinions On 308 Twist Rates

Thank You for the good reads , I had not come across these article before . Going to order a barrel tomorrow , still not sure which twist to get , may make that decision when I hit the buy button . Thanks all

 

[SIE107]

Re: Opinions On 308 Twist Rates

What is this facination of wanting to shoot the Sierra 168's at long range. yeah they would do fine in most rifles out to 800 yards, but that is it. Seriously folks, there are better long range bullets than the SIE 168 grain bullet. This bullet was designed to be shot at 300 meters.

 

[SIE107]

Re: Opinions On 308 Twist Rates

As for twist rate, decide what bullets your going to shoot, if your going to use up to something like the Hornady 208 gr Amax, then get a 11.25 twist. If your going to only want to go up to say a 190 grain bullet, get a 12 twist. Also be advised that the Berger 155.5 grain Fullbore bullet shoots better in a 12 twist than a 13 twist bbl.

 

[67rschev]

Re: Opinions On 308 Twist Rates

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SIE107</div><div class="ubbcode-body">What is this fascination of wanting to shoot the Sierra 168's at long range. yeah they would do fine in most rifles out to 800 yards, but that is it. Seriously folks, there are better long range bullets than the SIE 168 grain bullet. This bullet was designed to be shot at 300 meters. </div></div>

No fascination at all , that is just what shoots best in my long long throat stock Remington varmint barrel . I think the with shape of the ogave , the SMK is very forgiving for barrel where you have so much jump . Cost is another perk of the SMKs , they can be had very inexpensively . And where I shoot in summer , we can reach altitude air densities well over 11000 feet with the heat , and shoot well past 800 yards and stay mach to 1200 yards .

 

[Who Dat]

Re: Opinions On 308 Twist Rates

Here here, I have the 700 SPS varmint and I did the same thing and dropped it into a AICS. Only difference is I did not cut the barrel down it is still 26in. It has a 1-12TR and I shoot the 168gr Hornady BTHP Match at 2700fps and the groups are nothing to laugh at. When working on my group size I started at the standard torque setting recommended by AI for the action bolts and then started increasing torque at small increments until the group size became consistent. You just do not want to over torque the torque settings recommended by Remington. I plan on shooting my barrel out before replaceing it. You are right, about density altitude my range next to my house it at 9500ft and when I drop down to the front range I know what my change of impact will be fom the air getting thicker. The SPS varminter is a good rifle or Remington would not have come out with the SPS Tactical with the same twist rate.

 

[BruceWayne]

Re: Opinions On 308 Twist Rates

1:10 if its your only .308

 

[Downzero]

Re: Opinions On 308 Twist Rates

Mine is 1 in 12 and shoots the 175s just fine. I'd probably go 1 in 11 if I were you.

Or better yet, build a 7mm instead of a .308!

 

[IkeEng]

Re: Opinions On 308 Twist Rates

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body">Mine is 1 in 12 and shoots the 175s just fine. I'd probably go 1 in 11 if I were you.

Or better yet, build a 7mm instead of a .308! </div></div>

This goes for me as well. I took a Rem 700 Varmint and have dropped it into an AX chassis temporarily. I'm waiting on getting another 700 SA (.308) back that I have being trued and re-barreled in 6.5 Creedmoor. Once I have it back I'll yank out the varmint and drop in the 6.5 Creedmoor. Easiest decision I have ever made.

 

[SIE107]

Re: Opinions On 308 Twist Rates

12 twist is a very good all round bullet forgiving twist to use. Velocity and length of the barrel have a lot to play with it as well. Those fellows that have short bbl's, to a point, have to push it a lil more and use a faster twist to go beyond 800 yards in my opinion. The thing is, the new breed of 155 grain bullets out perform the Sierra 175 in many instances.

 

[pavementends]

Re: Opinions On 308 Twist Rates

I have never had issues with a 1;10 with bullets a light as 130 gr. and they heavies are fine. I don't think you can get a bullet moving fast enough in a .308 to come apart in the air.

 

[TCKev]

Re: Opinions On 308 Twist Rates

^^^^^^^ this. You can under spin one but can't see over spinning one. It's not like your shooting varmint bullet's.

 

[mikeylikesit]

Re: Opinions On 308 Twist Rates

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rprecision</div><div class="ubbcode-body">1/10 twist 168's to 200's

I feel that a bit to much twist is better the just enough.

In a .308/7.62 your barrel life will be the same with either </div></div>

+1 This is sound advise.