Try this link http://stevespages.com/page8e.htm It will give you the greenhill formula to figure your own bullet. Steve has almost anything you want to know somewhere in his site.
Posts: 2535 | Location: Michigan | Registered: 20 January 2001
The Greenhill calculation requires that you know the exact bullet length. If you have the bullets on hand, no problem. If you're interested in the necessary twist for other bullets, here is another option. Just click on the link below and go to "Recommended Rifling Twist".
Posts: 529 | Location: Missouri | Registered: 31 January 2002
Quote: The Greenhill calculation requires that you know the exact bullet length.
Right! The reason for this is that it is the length of a bullet, NOT ITS' WEIGHT, that determines how rapidly it must spin to remain point-on in flight!
What specifically are you trying to match up? calibre/bullet weight. Black powder twist rates vary markedly from smokeless. For a purpose built rifle with one bullet weight a slow twist may be preferable. One shooter here, built a 6mm/06 to get the most from the 55gn Nosler with a 1:14" twist rather than 1:10". Darn thing shoots like a dream!
Posts: 1785 | Location: Kingaroy, Australia | Registered: 29 April 2002
