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Old December 13, 2011, 02:00 AM   #1
deepcore
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1:10 vs 1:12 .308 Which is better all around(er)

Which twist rate is a better all around jack of all trades?
Keeping bullet weight ranges between 147 grains and 175 grains.

Looking at a new Remy 700 and trying to choose between the varmint 26 incher in 1:12 and the AAC 20 incher in 1:10.
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Old December 13, 2011, 02:21 AM   #2
kraigwy
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1:10.

Faster twist will shoot lighter bullets but slower twist wont shoot heavy bullets.
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Old December 13, 2011, 02:51 AM   #3
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twist rate

I agree 1:10 frm gnbrown aspiring gunsmith!
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Old December 13, 2011, 03:08 AM   #4
SR420
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1:10 ROT

Yep, all of my 7.62/.308 barrels have a 1:10 ROT...
I shoot everything from 147 grain NATO right up to 180 grain
subsonic 7.62 x 51 though a suppressor with excellent results.
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Old December 13, 2011, 08:15 AM   #5
old roper
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I think you have to make a choice as to which rifle you want to buy and you get whatever that rifle has vs which is the best twist.

Remington puts 1/10 twist on their short barrel 308 rifles and the 308 Varmint rifle 26" long barrel has 1/12 and their 308 tactical has 1/11.25r barrel.

The short barrel your looking at is suppressor ready. My gunsmith is a dealer for LMT rifle and his demo rifle is the 308 short barrel 1/11.25r twist and you think Rem would of used their 1/11.25r twist on that rifle and maybe it's pricing.

I'm not a fan of 1/10 twist 30 cal barrels so I'd vote for 1/12 twist barrel.
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Old December 13, 2011, 09:12 AM   #6
madcratebuilder
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For the 147-175gr bullet weights a 1-10 twist would be my choice.
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Old December 13, 2011, 10:41 AM   #7
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I thought .308 wasn't that senstitive and this only came up if one wanted to shoot sub-sonic rounds.
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Old December 13, 2011, 11:09 AM   #8
Brant
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Just go with 1/10

Heavyer bullets move less in the wind, and a faster twist stableizes heavyer bullets better. To get the most out of this round a 1/10 twist is probably the best to go with.
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Old December 13, 2011, 12:37 PM   #9
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I think I'll just stick with my 12 twist in .308 for up to 175 gr., especially if the bbl length is shorter. If I am shooting heavier bullets I'll go with a 10 twist in '06 or 300 Win Mag.
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Old December 13, 2011, 12:52 PM   #10
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I had an AI 1:12 would not stabilize for 800yds the 175 and 178 were flying all over the place
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Old December 13, 2011, 04:34 PM   #11
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Back in the 70's I did a lot of experimenting with this ,1 in 10 is the answer without any doubt.
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Old December 13, 2011, 04:49 PM   #12
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My Howa 1500 has a 1:12 24" barrel. It shoots 175gr SMK better than 168gr SMK's...but I have only shot it out to 300 yards.
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Old December 13, 2011, 05:54 PM   #13
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Ther is no problem shooting 168 Amax or SMK or 175 grain SMK out of a 20 inch in 1-10 at 300 yards . You don't need a 26 inch barrel for a .308 . A 20 in a 1-10 is going to be what you want .
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Old December 13, 2011, 06:27 PM   #14
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Here a good article on the 308

http://www.6mmbr.com/308Win.html
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Old December 13, 2011, 06:37 PM   #15
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1:10
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Old December 13, 2011, 08:46 PM   #16
Art Eatman
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'06 stuff, but...Years back I did a lot of varmint hunting with 110-grain bullets. My 1:10 twist let me get nice, tight groups. Works okay with the Sierra 180 SPBTs, as well. And, just for fun, adequate with 80-grain pistol bullets.

Odds are that a 1:12 is a bit slow for anything over a 165, but that's a bit of a "sorta-educated" guess.
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Old December 13, 2011, 09:41 PM   #17
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Thanks guys.
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Old December 13, 2011, 10:59 PM   #18
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I run 180g SGKs out of my gas gun with a 1:12 bull barrel. No stabalization problems to report even in cold conditions.
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Old December 13, 2011, 11:25 PM   #19
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My Sako .308 is 1/11 and shoots just great. Too fast and it can cause problems and increase barrel wear depending on the bullet being used. I've seen 1/10, 1/11 and 1/12 used by reputable MFG's. There may even be others?

Use this formula for the specific bullet you plan to use.

TWIST rate = D2 C / L x (sq root of ) SG/10.9
Where:
• C = 150 (*180 for muzzle velocities higher than 2,800 f/s)
• D = bullet's diameter in inches
• L = bullet's length in inches
• SG = bullet's specific gravity (10.9 for lead-core bullets)
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Old December 13, 2011, 11:26 PM   #20
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HK beat me to it.

11.25 i've shot 155s, 168s, and 175s through mine all sub-MOA. I wouldn't hesitate to go to 180-190 either. It might be the very limit of the 11.25 stabilizing the longer projectiles. I'll never have a .308 bolt rifle barreled with anything else than 1:11 or 11.25.
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Old December 13, 2011, 11:30 PM   #21
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Sorry Black!
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Old December 13, 2011, 11:45 PM   #22
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whether a bullet will stabilize with a particular twist depends on 4 things 1) length of the bullet 2)Diameter of the bullet 3) velocity of the bullet 4) specific gravity of the bullet.

Here is a online calculator which uses the Miller formula that should help you out assuming you know basically what bullet you will be loading and the appx velocity you can expect if you have a bullet to out a mike on. manufactures are not exactly free with that data and the easiest way would be to find a box an measure them. Play with it a bit and you will see that the lower the velocity the shorter the bullet has to be for the same barrel twist.

http://kwk.us/twist.html

using a .308 Berger 155.5 Palma bullet which is 1.4 inches long and which I shoot at 2775 I am good to go with my 1:12 barrel

Now to confuse matters even more the shape of the bullet affects the length. A 155 Gr SMK is 1.202 inches long because it uses a tangent ogive rather than a secant + tangent hybrid profile like the Berger. BTW the SMK's shoot just as well if not better in my gun than the higher priced Bergers do. A buddies same brand/model gun is just the opposite and loves the Bergers

if you want to know the hows and whys and want to get a math headache then this read this

http://www.jbmballistics.com/ballist...tability_2.pdf

but the bottom line is this, forget the math and get whichever gun you like the best and play with some bullets and powders to get the accuracy the gun likes the best. What do you plan on using the gun for varmints in N Dakota or deer hunting in Tennessee. Get the one that you would be happiest with, If you want to use it for LR then 1:12 155's will do you just fine, that is a s heavy as the 1000 yard Palma shooters are allowed.
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Last edited by hounddawg; December 13, 2011 at 11:54 PM.
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Old December 14, 2011, 07:43 PM   #23
30Cal
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I shoot my match M1A with a 1:12". This gets me 125's at short range (200yds) and 155/168/175's the rest of the way to 600yds. The M1A isn't as flexible with velocities, but for a bolt gun, I'd go with a 1:11 or 1:12.

I'd go with a 1:10" if I had a regular need for 180+grs. For daily use, I think the slower twists are much more versatile.
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Old December 15, 2011, 07:15 PM   #24
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The OP said all around jack of all trades 147 to 175 . To me this means long range hunting is on the table also. A 20 inch in 1-10 is going to be great for humping around the woods and takeing Deer and elk at range. As far as punching paper a 20 inch in a 1-10 is fantastic for 168 and 175,178 SMK or Amax .
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Old December 15, 2011, 08:56 PM   #25
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I'd want 24" for elk just to hit him harder, but i love 18.5s and 20" .308s so i agree with Gonif also
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