[Charlie]

What would be the idea twist for a 16 inch colt sporter pre band? It has a light weight 1-7 that I was going to change to a m4 style. Should I stay with 1-7 or go to 1-9? Any thoughts

 

[Guest]

from a really old thread

I was told that the Viet Nam round was a 70 grain bullet exiting a 20 inch barrel with a 1 turn in 12 or 14 inch twist rate. I was also told that the SS109 round is a 62 grainer optimized for a 20 inch barrel with a 1 turn in 7 inch twist rate. I was also told that the 55 grain projectile was optimal for a 1 turn in 9 inch twist and what the Military was going to standardize upon for regular line troops.
What is the real story ?

:hmmm: :assult:

 

[Gyrene]

The bullet weight that you choose to shoot will tell you what rate of twist you need. Some settle for the 1 in 9, because it is a reasonable compromise. Remember the heavier bullets shoot better with a faster twist rate (logic tells me otherwise, but that is how it works best.).

 

[TULAver]

SImple physics Gyrene. The heavier bullet needs a tighter spin to stabilize the flight path. Like throwing a Nerf football compared to a leather NFL weight one. Throw the nerf with the exact same motion and force as a Real football needs and it'll spin wildly off axis, too much spin for such little weight. Throw the Real football with the force and motion you use to get a perfect Nerf pass, and there won't be enough spin to stabilize it, resulting in the legendary Girly-Man Pass.