Is it possible to stabilize heavy bullets in slow twist barrels at slow velocities?

[msg.drew]

I have had this in the back of my mind for a bit... at what velocity would you have to fire an .224 80 grain bullet to stabilize out of a 1-12" twist barrel...

There is an rpm range where a 1-7" will stabilize that weight bullet at a velocity...

So is it possible to replicate that rmp range in a 1-12" fireing the bullet at lower velocity.

 

[pmt]

20,000fps. (Twenty Thousand feet per second)

With 11:1 you could do it at 12,000fps.

BTW, 1:12 is not a fast twist - it's a slow twist.

 

[msg.drew]

could you show me how you calcuated that...

 

[Levi Garrett]

their a bit heavy for that twist, I would not waste my time with those, and go for 55-60 grain.
But heck , give it a go

 

[scout]

Likely the Miller Stability formula ... Litz' book also comes with a Point Mass Ballistics Solver program that calculates the stability factor.

 

[msg.drew]

their a bit heavy for that twist, I would not waste my time with those, and go for 55-60 grain.
But heck , give it a go

I have been using 50 grainers out to 600 yards... some how I can stablize 69 grain bullets in the 1-12 twist so I am going to give those a shot next time.

 

[SandRoad]

The original M16 rifles had a 1:14" twist, and they stabilized 55 grain bullets without problems. When the army officially adopted the rifle, one of the changes was to a 1:12 twist.

The overall lenght of the bullet will also be a factor for the minimum twist rate to stabilize it. A short, blunt bullet will stabilize at a slower twist rate than a longer pointy, boattail bullet of the same weight.

 

[762nato]

may or may not work, give it a try.

 

[pmt]

Likely the Miller Stability formula ... Litz' book also comes with a Point Mass Ballistics Solver program that calculates the stability factor.

Yep, just f**kin' around putting different numbers in until I got 1.3 -1.4 ( using Sierra 80MK's)