Bullet stabilisation

I was wondering, is the important factor in bullet stability distance or time? If a given projectile is rotating a bullet in a certain twist barrel, does the twist have to be the same irrelevant of speed, or will speeding up the bullet allow you to open up the twist rate?

Comparing 300 blackout to 300 winmag, if shooting the same projectile would the same twist need to be used, or would the greater speed of the 300 winmag allow a slower twist to get the same revolutions per second to stabilise the same, or would you require the same revolutions per metre?

Hope the question is a bit clearer than mud, but let me know if I’ve confused you. Sadly it’s not related to any upcoming purchases, just curiosity

Yes sending the bullet faster will compensate a marginally stable bullet. In practice im not sure if the effect is really that significant. I would always choose my barrel to suit the projectile that I wanted to fire.


Off topic, but how good is this. No bullshit, no internet experts seeing who can google the fastest, just a simple practical answer from an accuracy OCD mofo who shoots long range competitively.

Just need the rest of the OCD squad to contribute @Gwion @Brett @Gregfiddich

For me twist rate is determined by bullet design including sectional density and bearing length. Velocity does impact stability but as sungazer said it is minimal compared to the other factors. The berger stability calculator (Twist Rate Stability Calculator | Berger Bullets) would be a good one to play with if you wanted to know the actual impact.

Drag and velocity have a closer relationship than twist and velocity.


Thanks to you both, great to have some practical knowledge and experience to draw off. I thought there would be more to it than just length and twist

What those guys said: especially the bit about bullet design.

Choose a task for your rifle and set it up to achieve that task.

As Greg alluded to, bullet length is often confused with bullet bearing length (part contacting rifling) when it comes to choosing bullet weight for twist rate.

More mass on the bullet will carry it further with more energy but only if it is aero efficient enough (want of better term here).
Something about moment of inertia, etc, etc.
Basically, the back of the bullet ends up wanting to over take the front of the bullet and upsets it stability. As the bulk of a bullets mass is behind the thing slowing it down (the atmosphere), this is always going to happen… question just is how long will it take…

Mass provides momentum
twist provides gyroscopic stability
Design provides drag or lack there of
Velocity provides inertia

Or something like that; I’m not a physicist so my terms are probably jumbled.

Balancing the above to achieve desired terminal effect is what bullet selection is about… as I understand it.

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