Question about twist rate 308win.

A 12 twist may never be able to stabilize a long heavy bullet like a 220, but I'm not sure the theory of bullets "going to sleep" has ever been proven.

If you're planning on 155s you might be able to get away with a 10 twist (my Broughton loves them) but I think you'll find a 12 twist more suited for the lighter bullets, and your load development should take no time at all.
 
I really like Shilens .338 caliber twist choices and description.

Apparently you can get:

" an 8 twist for all bullets" Or

" a 10 twist for all bullets"


:D
 
In this case, Shilen is correct. There is no 338cal bullet that doesn't stabilize in a 10 twist using a larger case like the Lapua.

some may want to go subsonic loads and then the 8 twist will work.

so they are right :)

OP, load up the bullet and shoot it. There are zillions of 10 twist 308s being shot every day. 155's are tolerant of twist rate so keep pressure moderate and if the barrel will shoot, you will find load.

Only one way to find out...

Jerry
 
For best accuracy, use the slowest twist that will stabilize the bullet used in all conditions. True-Flite has accurate comments on their site. 1-12" in .308Win will stablize all 185-190 grain bullets and 1-13" will handle all 155 grain bullets. Generally, we use twists faster than required. Being spun faster than required has more negative effect on bullets with less concentric jackets.

Regards,

Peter
 
When I first got my .308, 1 in 10 twist I was shooting 110gr TAP beautifuly. Its just hard to find that here so I moved up to 150gr Hornady and dought I will go bigger. I've tried 168's and dont see much difference out to 300 between the two.

Back in NL, I used to shoot 180gr out of a 1 in 12 twist for hunting with out problems. So it comes down to what your rifle likes. Try a little bit of everything!
 
Bandits, John Whidden is a shooting marvel, using unconventional kit , Win Md 70 with 1-10 twist and 155 bullets to win a lot of top matches. David Luckman, GB, argueably the best longrange shooter in the world, won at Perry this year with 1 pointand 1 vee over Whidden.

However, the theory put forth by BR shooters about the slowest twist to stabilize for best accurracy stands.

Regards,
Peter
 
whether the bullet itself is affected is a moot point. too much twist on a large caliber like a 30 induces a great deal of torque on the gun. A bullet slamming into tight rifling under tens of thousands of pounds of pressure doing thousands of feet per second will cause the gun to torque and twist. Watch someone using a harris bipod and you will see what i mean. THAT will affect consistency. short range benchrest is about using short bullets with slow twists. That reduces torque and helps with group sizes. FWIW, I have used 208 Amax's out of a 12 twist and they shoot just fine. 12 twist is about all you need with a 308

if using a 10 twist, look for 155's that have the shortest bearing surfaces and see if you can get them working
 
Twist is but one variable in a barerl's ability to shootwell. probably the least significant, unless there is not enough spin. Barrel quality, and chambering and set up are far more important.

If you want to shoot 155's, a 1:14 or 1:13 would be a good choice. A 1:12 is a good all round twist. A 1:10 is good if you want to shoot real long heavy bullets, like a 210VLD.

If you like the rifle with the 1:10 (Savage?) then buy it. I doubt you could ever see any difference in grouping because of the faster twist, especially with quality bullets.

A bullet is generally stable by 100 yards (it has stopped yawing) and then gains stability as it goes down range. The RPM does not slow very much, but the velocity drops, causing less air compression. The denser the air, the higher the required RPM.
 
My 1:10 twist 20" barrel on my Remington did not like the 168 grainers other than nosler match ammo. It loves 180 grains doesn't matter what type though some do better than others
 
interesting stuff.... I found my 1:10 bbl loves shooting 150 grn factory winchester accu bond at 100/200 Y. But in the near future i will be starting handloading the .308, and my first bullet choice will be Hornady 178 gn BTHP's, with the idea to shoot at 600+ Y, but I will test 100/200 y extensively as well. :)
 
You must log in or register to reply here.
Back
Top Bottom