.308 twist 185 Juggernauts re-barreling

[dsbur]

My .308 3-groove Benchmark #8 contour at 29.75" is getting a little tired at 5000 rds, it's an 11" twist and I have been doing very well with the 185 Juggernauts (current High Master in F-TR LR)

I have an opportunity to re-barrel and upgrade my action. Have been talking with my local scoundrels and the suggestion is to go to a 10" twist. Looking at the Heavy Palma contours for a little more weight.

I don't care to shoot the 200-215gr bullets for recoil reasons mostly. That said, does anyone have any comments on twist rates for the 185 Berger family (hybrids, Jugs)? The equipment lists from SW Berger don't give enough details on the barrels.

Berger website shows either twist acceptable with the 10" having a greater 'stability factor', whatever that means.

 

[Monte F]

I have a 10 twist, 28", bull barrel on my rifle shooting the 185 jugs. Tried 200.20x and 208 ELD-M, didn't have much luck getting them to shoot as well. And as you said has more recoil/fatigue, may be better in heavy winds though.

 

[msinc]

The Army spent considerable time and money to conclude that 1-in-11.75 was "optimal" twist for match M-14's shooting 168 grain BTHP match bullets. They contracted Maremont, one of the makers of the M-60, to make heavy match barrels for the AMU. I had one on my M1A and it did shoot that bullet very well. Later when I wanted to shoot 190 grain BTHP match bullets I went to a Krieger 1-in-10 twist match barrel. Prior to the barrel/twist change I tried the 190's at 600 meters when it was windy, just like many others. You could tell who had a less than 1-in-10 twist shooting 190's on a windy day when you worked the pit at 600. You could actually hear the bullets making a buzzing noise because they were tumbling.
What they are talking about when they discuss different twists that will work is that range is a factor. I couldn't tell any accuracy or stabilization difference at 100 or even 200 yards with either 1-in-12, 1-in-11.75 and 1-in-10, but get out there a ways and it started to loose stability. There is a limit of course...you wont do too good at even 100 yards with 77 grain bullets in a 1-in-14 twist varmint barrel.
Bottom line...use the 1-in-10. In this caliber that is not too tight of a twist for the lighter bullets...it will still shoot them just fine, but it will stabilize the 190's. I have not used any other twist in every 30 caliber rifle I have built in the last 20 plus years and they all shot very good.

 

[Toejoe12]

I'm really not trying to be a smart ass with this question.......why would you even be thinking about changing a thing from your current barrel set up if you've been able to make HM in long range FTR with this set up and 185Jugs? There are very few HM in LR in FTR currently. That is a huge accomplishment on it's own from 1000yds with a 308. Stay with your current set up and replace the barrel with the exact same thing that has given you that success!!

 

[Stingray]

I'm really not trying to be a smart ass with this question.......why would you even be thinking about changing a thing from your current barrel set up if you've been able to make HM in long range FTR with this set up and 185Jugs? There are very few HM in LR in FTR currently. That is a huge accomplishment on it's on from 1000yds with a 308. Stay with your current set up and replace the barrel with the exact same thing that has given you that success!!

Ditto^

 

[Warren Dean]

Team USA won both the 4 man and 8 man team matches at the 2013 world championships with 12 twist barrels, for whatever that's worth.

 

[Scott Harris]

My .308 3-groove Benchmark #8 contour at 29.75" is getting a little tired at 5000 rds, it's an 11" twist and I have been doing very well with the 185 Juggernauts (current High Master in F-TR LR)

I have an opportunity to re-barrel and upgrade my action. Have been talking with my local scoundrels and the suggestion is to go to a 10" twist. Looking at the Heavy Palma contours for a little more weight.

I don't care to shoot the 200-215gr bullets for recoil reasons mostly. That said, does anyone have any comments on twist rates for the 185 Berger family (hybrids, Jugs)? The equipment lists from SW Berger don't give enough details on the barrels.

Berger website shows either twist acceptable with the 10" having a greater 'stability factor', whatever that means.

I personally have standardized on 10 twists because they shoot a wide range of bullets very well: all the 185 to 200 grainers. But for only the 185-class bullets, the 11 twist would be my choice. Bryan Litz has popularized fast twists to maximize BCs. But there is another theory: only spin the bullet as fast as necessary to stabilize it for best accuracy. The idea here is "imperfect" bullets shoot larger as you spin them faster. Blending both these theories together: spin it fast enough to get the sG at 1.50, but no faster.

Using the Berger twist-rate calculator, an 11-twist with 72 degree temp, 2750 vel, 185 Hybrid....1.48 sG....just about perfect.

 

[1shot]

I'm really not trying to be a smart ass with this question.......why would you even be thinking about changing a thing from your current barrel set up if you've been able to make HM in long range FTR with this set up and 185Jugs? There are very few HM in LR in FTR currently. That is a huge accomplishment on it's on from 1000yds with a 308. Stay with your current set up and replace the barrel with the exact same thing that has given you that success!!

On the other side of that coin, just because your current barrel/rate of twist is working well, doesn't mean that a new tube with the same "advertised" rate of twist will shoot as well. Have you ever measured the "actual twist rate on your current barrel? It could be faster than the number stamped on it.
I shoot a 1-10 in a 5R configuration and it shoots the Juggs very well.
I hope this helps,

Lloyd

 

[swadiver]

1 in 10 or 1 in 11 will work very good. wind reading will trump this decision

 

[Liven The Dream]

Mostly a Palma shooter.
I am on the Trip to the Dark Side.
Built a FT/R Rifle 30" HV Palma 1-10 it shoots 185's very well and 168,175OTM"s .

Like above if not broken why fix it ?

 

[dcali]

If you’re not interested in heavier bullets, stick with what you’ve got.

 

[XTR]

Lots of people have shot the Juggs in 10's, 11's, 11.75's, and even 13's. It's not going to have much of an effect one way or the other.

 

[Ned Ludd]

Another vote for 11-twist and sticking with what you already have that is working. I shoot both the 185 Juggernauts and 185 Hybrids out of 30" 11-twist barrels and that twist is plenty. FWIW - I also shoot the 200.20X bullets and JLK 210s out of one of those rifles that has a slightly longer freebore (0.180"). Although I may be giving up a slight amount of their intrinsic BCs by not using a 10-twist, both of those bullets shoot very well out of an 11-twist barrel. So you're not strictly limited to 185 gr bullets if you go with an 11-twist.

 

[ahusted1978]

I have great luck with the Juggs, .010 off in a 30", 1:10, 5r