Hunter2 Posted December 10, 2009 Report Share Posted December 10, 2009 Hi Can someone point me in the right direction of understanding barrel twist rates Regards Derek Quote Link to comment Share on other sites More sharing options...
phil1964 Posted December 11, 2009 Report Share Posted December 11, 2009 http://www.ammosmith.com/rifle-reloading/d...arrel-twist.php Quote Link to comment Share on other sites More sharing options...
flytie Posted December 11, 2009 Report Share Posted December 11, 2009 http://www.chuckhawks.com/rifle_barrel.htm ft Quote Link to comment Share on other sites More sharing options...
macca Posted December 11, 2009 Report Share Posted December 11, 2009 Basically, pointed projectiles shot point first are inherently unstable. Spinning the projectile stabilises it (stops it from tumbling). Generally for a particular calibre - the longer the projectile the faster the twist rate required to spin the projectile fast enough to prevent it from tumbling. ie for 223 80 grain sierra a 1 in 8 twist is required Cheers Quote Link to comment Share on other sites More sharing options...
yellow11 Posted December 17, 2009 Report Share Posted December 17, 2009 You need a load that achieves a gyroscopic stablisity factor of 1.4 or higher. Do a search for Don Miller's twist formula and dial in fps, bullet length and weight. Basically, the longer the bullet the greater the yaw and therefore the higher the twist requirement I have attached (fingers crossed) a s/sheet that I knocked up for my 6x47 Lapua. You can alter the valued top what ever you need - hope it helps JH Twist_logic_sample1.xls Quote Link to comment Share on other sites More sharing options...
Hunter2 Posted December 22, 2009 Author Report Share Posted December 22, 2009 Thanks Guys all helpful Quote Link to comment Share on other sites More sharing options...
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