1:10" vs 1:12"

[NWARvet]

would really appreciate any input, choosing a barrel blank for a .308win build. anyone used 1:12" for a .308win

 

[10XSHOOTER]

Don't if you want to shoot anything over 150 gr bullet
Make it a 1=10 for anything up to 180 gr

 

[Ranger188]

Need to know what bullet or weight range you want to use.

 

[Mike TackleBerry]

I would go with a 10T hands down. 308 Win and 168 SMK with IMR 4064 have shot very well for me.

 

[Bob3700]

My Palma rifle is a 1-12T and I shoot 155 n 185 gr bullets. The 185 s shoot well at 1000 yds.
1-10T is the norm if bullets over 180-190 gr. are in the mix.

 

[WAMBO]

A 1-12" twist works fine with a 175 SMK at 1K, anything heavier or farther I would use a 1-10".

 

[Rob01]

Go with the 10 twist. Faster is better to err on the side of stable even with 155+ weight bullets. No downside to a 10 twist.

 

[ISS]

Vietnam Vet here, thank for your service!

1:12 is marginal, the 1:10 works for up to 200gr.

once: Sgt Rich

 

[L.Sherm]

Maybe I'm abnormal but I dont believe in spinning a bullet any faster than normal it hurts jacket integrity and accuracy in my opinion. Ive shot alot of 10 twists in 30 cals with 210-215 and all have shot outstanding.
Why don't you split the difference and go 11?

 

[Rob01]

10 twist hurts nothing in 168-190grn bullets in the .308.

 

[Desert Fox]

My 308 has 12 twist PacNor Super match. I can shoot bullet from 155 on up to 178 grain accurately.

 

[jpjulian]

The one .308 I have has a 10 twist but the barrel it replaced was an 11 twist, and the 11 twist shot better. But that was around 1994 and I've killed an awful lot of brain cells since then so my memory may be a bit foggy. But as L.Sherm said above, you can split the difference with an 11.

 

[dryhumor]

would really appreciate any input, choosing a barrel blank for a .308win build. anyone used 1:12" for a .308win

You never stated what the use would be. Hunting, plinking, yardage.

I shoot a 13 twist. 115-155 grain. Have had 10, 11.25, and 12 through the years. If i did it again, I’d still choose a 13T, It’ll do pretty much all I want to do. As a plus, pretty much any 150 grain factory deer ammo I’ve tried will be deer accurate out of the box, in a pinch.

Out of the 10 or 12 twist question, I’d say an 11.25 was a better thought for all around. I’ve had several, and it is a good twist to accommodate 165-168 grain.

 

[AckleymanII]

I have 10,11,12, 14, 15 twist 308s.

The 12 twist stabilizes the 175g Sierra tipped match king very accurately, 3/4" groups at 300 with 42g of IMR XBR 8208, Lapua case, cci BR-2.

The 15 Twist-24" is a deer rifle, 125g Sierra TGK at 3300 shoots a single bullet hole group. The 14 Twist,24" shoots the 150g Sierra and Hornady Flat Base at 2950.

It takes energy to twist a bullet. You can use that energy for generating twist or speed....pick.

 

[NWARvet]

Vietnam Vet here, thank for your service!

1:12 is marginal, the 1:10 works for up to 200gr.

once: Sgt Rich

and thank you for yours sir,
once: SGT Coffin

 

[Fuj]

A 12 twist will cover more then one thinks. A 180 and even a 190 grain
bullet can be stable. It's the length of the bullet and not the weight.

Here's a little exercise on JBM......Take a 180 SMK that has a length of 1.277".
Using a 12 twister with a speed of 2600 fps, your stable......I prefer myself
the least amount of twist for what the rifle will be used for......

 

[Fuj]

One more but going to a 14 twist with a 150 SMK at 2750 fps......

Just know what bullet profiles you plan to use and calculate from
there. A big problem Is when one wants to jump from a more tangent
type of bullet to a bullet that is more in the VLD type. A VLD will be
much longer and would require a faster twist......Anyone needing a
quick check for anything, JBM is a good one to keep bookmarked.
It does try to keep current with bullet lengths by company but, always
check your own lot and use that number......Green is stable, yellow is
marginal, and red a nogo......

 

[Liven The Dream]

A 1-10 is dandy. Old Standard. Now as for old.
Boots Obermeyer made a 1-11.5 R5 back in the day. That was the M-14/M1A Barrel to have.
He had Many Gov. Contracts for Barrels. RIP.

 

[kevinbritvec]

I prefer 1:10 for all .30 caliber rifles, unless I want to shoot bullets weighing 210 grains or more, 1:9 works for them.

1:12 is common in production hunting rifles, 1:11.25 or faster for tactical/target rifles is the norm.

 

[Springer2]

Many 308 hunting rifles were 1:10 which worked fine across most all bullet weights. In the days when the 168 match bullet was the preferred target round, 1:12 was usually selected. This is our mod 70 ISU rifle in 1:12 with 168 match @ 100 yards.