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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Berger keeps changing twist requirements
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<blockquote data-quote="barefooter56" data-source="post: 1509538" data-attributes="member: 85389"><p>Ok, Here is what is going on. For a long time we did the OPTIMAL TWIST RATE thing based on 59 degrees at sea level. But some shooters were confused by this and thought that this was the ONLY barrel twist rate that would stabilize that particular bullet. Not true. A SLOWER twist rate can work to stabilize the bullet also BUT the BC is affected. So now we have gone to a MINIMAL twist rate needed to stabilize a bullet. This also goes to the TWIST RATE CALCULATOR on our website:<a href="http://www.bergerbullets.com/twist-rate-calculator/" target="_blank">http://www.bergerbullets.com/twist-rate-calculator/</a>. The center section of the bar graph has a heading on it that states "MARGINALLY STABLE" (bad term). This DOES NOT MEAN THAT THE BULLET IS UNSTABLE as some think. The SG (stability factor has to be BELOW 1.0 on the graph for a bullet to be unstable ( I fudge this to 1.2 for a cushion. You do what you want). From 1.0 on the bar graph to 1.49 SG should be read to mean that the bullet WILL BE STABILIZED. HOWEVER THE BC IS COMPROMISED DUE TO THE TWIST RATE OF THE RIFLE. This "compromised" BC will be shown as a number and a percentage above the bar graph. This is the BC number to use when doing your ballistic calculations! Please ALWAYS ENTER the ALTITUDE(S) you will be shooting at to get accurate data on BOTH the BALLISTIC and TWIST RATE CALCULATORS. If you are trying to find what twist rate you may want to use if building a rifle. Base your barrel twist rate choice on the LOWEST ALTITUDE you will be shooting at! 1.5 SG or slightly above that is a good place to be for a Hunting rifle since we use the SAMMI VELOCITY OF 1800FPS AT THE ANIMAL FOR ADEQUATE BULLET PERFORMANCE FOR ALL OF OUR HUNTING BULLETS.</p><p>Our apologies for any confusion on this. We will be revising the verbiage on the Twist rate calculator at sometime in the future. Right now it all hands on deck to get caught up and ahead on the production of our 6.5 bullets and anything else we are behind on.</p><p>If you have any questions please contact me here or at the phone number below.</p></blockquote><p></p>
[QUOTE="barefooter56, post: 1509538, member: 85389"] Ok, Here is what is going on. For a long time we did the OPTIMAL TWIST RATE thing based on 59 degrees at sea level. But some shooters were confused by this and thought that this was the ONLY barrel twist rate that would stabilize that particular bullet. Not true. A SLOWER twist rate can work to stabilize the bullet also BUT the BC is affected. So now we have gone to a MINIMAL twist rate needed to stabilize a bullet. This also goes to the TWIST RATE CALCULATOR on our website:[URL]http://www.bergerbullets.com/twist-rate-calculator/[/URL]. The center section of the bar graph has a heading on it that states "MARGINALLY STABLE" (bad term). This DOES NOT MEAN THAT THE BULLET IS UNSTABLE as some think. The SG (stability factor has to be BELOW 1.0 on the graph for a bullet to be unstable ( I fudge this to 1.2 for a cushion. You do what you want). From 1.0 on the bar graph to 1.49 SG should be read to mean that the bullet WILL BE STABILIZED. HOWEVER THE BC IS COMPROMISED DUE TO THE TWIST RATE OF THE RIFLE. This "compromised" BC will be shown as a number and a percentage above the bar graph. This is the BC number to use when doing your ballistic calculations! Please ALWAYS ENTER the ALTITUDE(S) you will be shooting at to get accurate data on BOTH the BALLISTIC and TWIST RATE CALCULATORS. If you are trying to find what twist rate you may want to use if building a rifle. Base your barrel twist rate choice on the LOWEST ALTITUDE you will be shooting at! 1.5 SG or slightly above that is a good place to be for a Hunting rifle since we use the SAMMI VELOCITY OF 1800FPS AT THE ANIMAL FOR ADEQUATE BULLET PERFORMANCE FOR ALL OF OUR HUNTING BULLETS. Our apologies for any confusion on this. We will be revising the verbiage on the Twist rate calculator at sometime in the future. Right now it all hands on deck to get caught up and ahead on the production of our 6.5 bullets and anything else we are behind on. If you have any questions please contact me here or at the phone number below. [/QUOTE]
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Berger keeps changing twist requirements
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