3006 and 1/10 twist what bullet weight

[grizzly416]

my 06 has a 1/10 twist shoots decent with 168sierras could i use the heavy hornadys(208gr) and will it be more accuratte or just stabilze better at long range

 

[Ganderite]

The 168 is a very good short range bullet designed for 300 meter shooting. Your 30-06 has the oomph to shoot 180 to 200 gr match bullets which will handle the wind much better at longer range.

 

[Obtunded]

Twist rate is tied to the LENGTH of a bullet.

In an '06 you could easily shoot the 210 grain Berger LD Match bullets (that only spec' a 1:11 twist) but there is a direct relationship between twist and speed as well. I wish bullet maufactuers would publish more data on RPM needed because a 1:10 in a 300 WM and a 1:10 in a 300 Whisper are two completely different animals.

Furthermore, magazine dimensions restrict bullet length choices.

Hard to beat a 175 SMK or a 178 Amax...

 

[gunrunner8]

Twist rate is tied to the LENGTH of a bullet.

In an '06 you could easily shoot the 210 grain Berger LD Match bullets (that only spec' a 1:11 twist) but there is a direct relationship between twist and speed as well. I wish bullet maufactuers would publish more data on RPM needed because a 1:10 in a 300 WM and a 1:10 in a 300 Whisper are two completely different animals.

Furthermore, magazine dimensions restrict bullet length choices.

Hard to beat a 175 SMK or a 178 Amax...

X2 Firearms factories are very conservative about twists. Once, I had 30-06 with 1/12" twist, and there was no problem to stabilize 200gr Nosler Partition SP, even past 300 yards. Acording to Grinhill formula, they should tumble. My Sportco 44 308 Win, also with 1/12" twist will stabilize Hornady 190gr BT to 500yds with no problem either.

 

[44/40]

If you go to any of the major barrel manufacturer websites, you can usually find a rate of twist chart that will tell you what the heaviest bullet weight your twist will stabilize - generally NOT including the longer VLD's.......I usually look at the Berger website for the recommended twists on the long ones. Here's a quick link for ya: http://www.shilen.com/calibersAndTwists.html

 

[rnbra-shooter]

And if you go to the bullet manufacturer's web sites, they will often list a required twist rate (especially for match bullets, or unusually long and heavy ones). Or you can email or phone their tech support lines and ask them. (FWIW, most bullet manufacturers, especially American ones, are extremely conservative with their minimum twist recommendations - you can nearly always get away with a slower twist than they state, and still have things work OK).

Or you can use the Greenhill formula to calculate it yourself. There's a good writeup (section "Twist rate") here: http://en.wikipedia.org/wiki/Twist_rate

The Greenhill formula in that Wikipedia entry probably looks a bit intimidating, since it includes a bullet density correction factor underneath a square root symbol, etc). A simpler version is:

C = Tw * L

Tw = barrel twist rate, in "calibers per turn"
L = bullet length, in "calibers".
C = calculated stability factor; should be no more than 150


So for a .308" barrel, a 1 in 12" twist would have Tw = 12"/.308" = 38.96 calibres per turn

A .308" bullet that is 1.1" long would be L = 3.57 calibres long

Using these we get C = 38.96*3.57 = 139. Since this is less than 150, Greenhill says it will be stable.

 

[Mystic Precision]

my 06 has a 1/10 twist shoots decent with 168sierras could i use the heavy hornadys(208gr) and will it be more accuratte or just stabilze better at long range

Depends on how far Long means to you.

There is only so much energy in that case so will do essentially the same work with 155's or 208's.

You can either go fast with the 155's or slow with the 208's. If you compare the numbers in a ballistics program, the drop of the 155's will be substantially less out to 800yds but drift might be a schnick more.

If your plans include going beyond 1000yds, then go 208/210gr VLD's. Both bullets would be going slow but the heavies will do better at extreme distances. At some point, high BC trumps muzzle velocity.

As for mechanical accuracy, your barrel is the limiting factor. I don't think you will see a sig difference between bullet weights (except maybe the amount you flinch). You might between manf.

There is only one way to find out...

Jerry

PS I would go 155 cause I hate recoil and I have shot the heavies.