30-06 twist rate ?

Waterengineer

New member
Is a 1:10 twist enough to stabilize a 180 gr. pill out of a 30-06?

Is there a source or computer "guestimate" program that helps figure this out?

Thanks, ahead of time.
 

koolminx

New member
What will tell you what bullet will work with a given caliber? Twist rate plus length of bullet plus depth of grooves?

Something akin to that?
 

Chipperman

New member
It's more complicated than that. Bullet construction/composition and powder charge also need to be taken into account.

Look at the links that darkgael provided.
 

darkgael

New member
yes

The answer in general terms - without the why's or formulae - has already been given. Yes, a 1-10 twist wil stabilize a 180 grain .30 cal bullet. I have fired bullets as heavy as 250 grains from my .30-06s and had no indication of instability at the short ranges at which I shot (100 yards).
Barnes makes one of their "original" bullets - a RNSP - as a 250 grainer. It looks like a stubby gilded pencil, quite long. I was attempting to duplicate the ballistics of the .318 Westley Richards - a 250 grain bullet at 2400 fps. It worked.
Pete
 

Scorch

New member
Bullet construct/composition have nothing to do with it. The required information is velocity and length of the projectile in multiples of its diameter (calibers). Along with the rate of twist, this will give you the angular velocity in RPM (revolutions per minute). The Greenhill formula will tell you how fast you need to spin a projectile of a given length (in calibers) to stabilize it. Weight does not come into the calculation. People mention weight because cup and core bullets of a certain design get longer as they get heavier, but just because they are longer does not mean they are heavier.

If this sounds confusing, think of a boattail hollowpoint VLD profile bullet compared to a round nose flat base bullet of the same weight traveling at the same velocity. The boattail hollow point bullet will be longer than a flat base round nose bullet, and would require a faster twist to stabilize it.

Realize also that manufacturers typically put barrels on rifles that will stabilize the heaviest bullet commercially available for that rifle, so a 1:10" twist barrel on a 30-06 will properly stabilize a 220 gr flat point spitzer bullet. The USMC M40A1 and A3 sniper rifles have a 1:11" twist to stabilize 168 gr and 172 gr bullets used in those rifles.
 

Waterengineer

New member
The reason I asked the question is that I am looking at a new-to-me rifle and I thought perhaps the reason it was for sale is the slow twist.

I have satisfied myself the 1:10 twist will work.

Thanks for all the dialogue and links to other pages.
 
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