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Determining optimal rifle twist using the Greenhill formula.

1307 Views 4 Replies 4 Participants Last post by  B27
I got a question from someone on youtube asking why rifling and bullets in general haven't changed much over the years. His message boiled down to him wanting to know why we don't try to make better rifling to improve accuracy. Obviously there are a number of things wrong with his question but I don't think a lot of new shooters understand rifling or how we determine what twist will gyroscopically stabilize a round.

So I made a video explaining the Greenhill formula and how we determine what twist to use with different projectiles. I also talked about needing a faster twist with subsonic and things like that.

I figured someone here might be interested in it. The video involves math so I'm not sure how popular it will be.

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interesting. i take it this applies to handguns also?
there. I finally learned something today. now I'm going to bed
interesting. i take it this applies to handguns also?
Sure. It works with any projectile. It was originally intended for use in rifled artillery. We have more precise methods for determining twist but this equation works fine for most applications. It's also the easiest to explain.
Most informative!
Thanks! :)
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